The appendages of the crayfish attach to both the cephalothorax and the abdomen. They are closely related to the lobster. Females, PROCEDURE
They are free to remain submerged for as long as they want. Note how the carapace extends over the head and between the eyes, this structure is called the ROSTRUM. Crayfish, common in streams and lakes, often conceal themselves under rocks or
Finish the Crayfish Dissection Review in JupiterEd to complete
What is the function of the heart? Animal Gaits Put on safety goggles, gloves, and a lab apron. 13. Label these two areas of the crayfish on your lab data sheet. On the thoracic region, locate the prominent suture or indentation on the cephalothorax that defines a central area separate from the sides. Young crayfish are more likely to be the
15. Locate the base segment of each pair of walking legs. A dead fish worms, corn, and salmon eggs are also favourites of the crayfish. into three distinct parts: the "claw" is formed from the propodite
Rostrum works as a stiffening rib layout structure. Its main function is to protect the crayfishs eyes and brain. 3. travel to the intestine which will expel the undigested waste
larger of the sensory structures on the head of a crayfish, smaller of the sensory structures on the head of a crayfish, the lower part of a crayfish; where the term and swimmerets are located, appendages that create water currents over gills, function in reproduction, and are used for swimming, part of the tail of a crustacean used for propulsion (in the middle of the tail), the large claws that the crayfish uses for defense and to capture pray, upper part of the crayfish; where the carapace and walking legs are located, the part of the exoskeleton that covers the cephalothorax, the sixth segment of the abdomen; found on each side of the telson in the crayfish, the first three appendages on the cephalothorax, hold food for eating, David N. Shier, Jackie L. Butler, Ricki Lewis, Andrew Russo, Cinnamon VanPutte, Jennifer Regan. Crayfish Dissection Lab Video Part 1, Click
10. move. They create water currents and function in reproduction. The head has 5 pairs of appendages. This is the crayfish's abdomen Its paired appendages are the swimmerets and uropods 4. It connects to walking legs (pereiopods), maxillipeds, whiskers (antennae and antennule), and eyes of the shrimp. : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Investigation:_Measuring_Lung_Capacity" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Investigation:_Rat_Dissection" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Investigation:__How_Does_Exercise_Affect_Heart_Rate?" Use the diagram below to locate and identify the organs of the digestive system. The antennules are organs of balance, touch, and taste. If your specimen is a male, locate the testis. cephalic region of the crayfish. Note: If we look at the carapace from above, we can see the groove, that separates the head and chest regions. Internal anatomy of a crayfish: edible freshwater crustacean, with pincers on the two forelegs. If you total these together you get "ten" appendages. crayfish. The ratio fL/f0f_{\mathrm{L}} / f_0fL/f0 is 0.800 . Urea, or uric acid, produced by some of the more terrestrial forms, is much less toxic than ammonia. See the pictures below for
them locate predators and allow them to swim to safety. External anatomy of a crayfish. This crucial organ is involved in the digestion of food, the transport of food, the release of digestive enzymes, and the storage of lipids, glycogen, and various minerals. swimmerets are all rather small and dainty. Bend the abdomen back and forth and observe how each segment moves. 2. Behind the chelipeds locate the four pairs of walking legs, one pair on each segment. Since they move so quickly, crayfish can be surprisingly challenging to catch. Now locate the two pairs of maxillae, which are the last appendages in the cephalic region. Swimmerets add more control when crayfish swim forward. As stated before, these are used for creating water currents for feeding as well
chelipeds and walking legs. She will use these swimmerets
The eyes of the crayfish are located beneath the rostrum. That is why biologists usually do not describe this part of the crayfish by itself. Carapace - The protective shell (exoskeleton) of the cephalothorax. In a male, the sperm duct openings are on the
First locate the antennules in the most anterior segment. thoracic regions of the cephalothorax. Dispose of your materials according to the directions from your teacher. above to locate the cephalothorax and the abdomen. The antenna starts in the crayfishs head, just behind the rostrum, and resembles wires. Apprentice & intern Isaac starting a fire @ summer camp. the leg attaches to the body. surface of the base segment of the THIRD PAIR of walking legs. These appendages aid the crayfish in food manipulation. The structure of the gills, which require a large surface area to absorb the most oxygen from the water flowing over them, is what gives fish their feathered appearance. segments. Telson. Use a magnifying glass to study the inside surface of the base segment of the third pair of walking legs. 2023 Copyright Shrimp and Snail Breeder, Even though the anatomy of crayfish varies from species to species, and yet there are basic physical characteristics that are identical among all crayfish species, from the, The part of the exoskeleton that covers the cephalothorax is called the carapace. the gastric mill which is used to help grind up the food for
The abdomen of the crayfish is segmented and flexible. Locate the digestive
The MANDIBLES of the crayfish are similar to the jaws of humans. At present, I am doing a Cert III Animal Studies assessment on the common yabby and need to give a brief description of their digestive system. This is the most muscular part of the crayfish. Next you will study the internal anatomy of a crayfish. From which view, dorsal or ventral, can you see the location of the appendages on the segments more clearly? appendages". 2. Crimean War - Cities, Straits, Isthmus, & Mntns, McCracken Path of the Blood through the heart and body, Ancient Rome Timeline to the End of Pax Romana. Most crayfish excrete ammonia through their gills as a by-product of nitrogen metabolism. We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. The
Undigested material passes into the intestine. "shield-like" structure that is connected to a few small
22. 5. 3. veins 109 Terms csharp34 External Anatomy your ankle (s) his/her ankle (s) my heel (s) gibikwaakoganaan (an) The sperm ducts that carry sperm from the testis open at the fifth walking leg. Materials: safety goggles, gloves, magnifying glass, a lab apron, plastic zip lock bag preserved crayfish, pen, dissecting tray, paper towels, scissors, forceps, dissecting needle, and dissecting pins. The three regions of the alimentary canals main characteristics are discussed below. For a variety of fish species, Seed shrimp offer a good source of Hi everyone! below shows all of these appendages: The segments
3. edges of the carapace, and extend it along both sides in the cephalic region. The External Anatomy of the Crayfish Prelab Questions: 1. They are most active at night, when they feed largely on snails, algae,
It protects their vital organs of any crayfish (brain, heart, stomach, bladder, testicular, or ovarian). Beneath the rostrum
Use the diagram below to locate the intestine. HERE for
Manage Settings This page titled External Anatomy of a Crayfish is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Shannan Muskopf (Biology Corner) . As shown in
Use the diagram below to locate the cephalothorax and the abdomen. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Why is it useful to view the specimen on its Dorsal side for this part of your study? ____. 9. ______________________________________________________________. The antennae are sense organs (touch, taste, equilibrium). _____________________________________________________________. The second pair of maxillae also helps to draw water over the gills. Both male and female specimens are examined. away the carapace too quickly, such action would disturb the underlying
8. of chitin, covers the dorsal surface of the cephalothorax. The smaller appendages attached to the segments of the abdomen are called SWIMMERETS. EXTERNAL ANATOMY: Observe the dorsal view of the crayfish below. 24. Telson never has any pleopods. 6. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The crayfish has an open circulatory system in which the blood flows from arteries into sinuses, or spaces, in tissues. Procedure Part 1External Anatomy of a Crayfish 1. The abdomen is flexible and the segmentation is visible here. The gut, which can absorb both, also regulates the overall balance of salts and water. Crayfish have gills that are primarily designed to breathe underwater. The feathery nature of the gills gives them a very large surface area. 1. Required fields are marked *. The cephalothorax in Greek translates as the head and thorax,. 21. If you
This structure should be hard and difficult to move. This is an excellent resource to practice identifying internal anatomical features of the crayfish prior to dissection. During its life cycle, the functional gland may change. contains the swimmerets) to expose the underside of the abdomen. uses these swimmerets to transfer sperm to the female. 7. Cut along the indentations that separate the thoracic portion of the carapace into three regions. The blood carries cellular wastes to the disk-like green glands. hairlike projections on the surface of the exoskeleton, often between the fingers of chelae, the sharpened bumps or projections on the carapace, the projections at the tips of the male reproductive structures (gonopods), the raised blunt bumps or projections on the exoskeleton, typically contrasting color to carapace. (c) Is the motion simple harmonic? cephalothorax is divided into 8 pairs of appendages: first two maxillipeds are
Crayfish Dissection Lab Video Part 2. 25. The roof of the pyloric chamber may be variously modified depending on the species diet. Click HEREfor and Illustrated Guide to the Dissection of the Crayfish PROCEDURE PART 1: External Anatomy of a Crayfish 1. Ana, summer staff, playing games @ summer camp. crayfish become sexually mature and mate in the October or November after
On this blog, I share all the things I learn about shrimp breeding as I go. The
Students, teachers and rockstars alike all come here to create and learn. any of the underlying structures while doing this. Behind them observe the much longer pair of antennae. In this article, I am going to talk about the external anatomy of the crayfish in detail. Your email address will not be published. Crayfish can either walk on the bottom of the ocean or lake, or use their urepods to propel them through the water. If you observe a crescent-shaped slit, you have located a genital pore of a female. Therefore, rapid,
The smaller one
Note the individual segments of the abdomen. Middle School Overnights (6-8th) ______________________________________________________________. This section will help you wade through the jargon-y maze of words used to describe the . Make small and shallow cuts so as not to disturb any of
The chelipeds are the large claws that the crayfish uses for defense and to capture prey. Clean up your work area and wash your hands before leaving lab. is located behind the cephalothrorax and consists of six clearly divided
They use them for internal fertilization. crayfish in the garbage and clean up your dissection tools and area. arteries. for and Illustrated Guide to the Dissection of the Crayfish, PROCEDURE
These are of two sets the antenna, the longer and thicker ones, and the antennules, the shorter ones. Crayfish have 3 pairs of maxillipeds (jawfoot, and foot jaw Origin: [Maxilla + L. pes, pedis, foot.]). PART 2: Internal Anatomy of a Crayfish. Locate the mouth. Rostrum (from the Latin rstrum meaning Beak) is a hard extension of the crayfishs carapace that prolongs forward of the eyes. The abdomen
If you must store your specimen until the next lab period, cover it with a dampened paper towel. The testis is the long, white organ under the heart and a bit forward. That indicates a female. In-service Training Give it a try! along the dorsal surface is known as the dorsal suture. On the thoracic portion of the cephalothorax, observe the three pointed maxillipeds. The segmentation and flexibility of the abdomen are evident here. 14. The indentation
_________. The dactylopodite is the moveable
Turn the crayfish with its DORSAL side upward, and locate the rostrum, which is the pointed extension of the carapace at the head of the animal shown in the diagram above. The carapace, a shield of chitin, covers the dorsal surface of the Craysh Dissection! Animal Tracks & Sign antennules in the most anterior segment, behind them observe the much longer
Besides defending against predators, crayfish use their claws to threaten their competitors. Each segment of both the cephalothorax and the abdomen contains a pair of appendages. Crayfish Anatomy The external structure of the crayfish is separated into two main sections, the cephalothorax and the abdomen. The
Which appendages in the cephalic region are related to the eating of food? The uropod and telson together make up the tail fan. Locate the dorsal tubular heart and several arteries. Rostrum protective plate between eyes. The rostrum is the portion of the carapace that extends over the head and in between the eyes in the cephalothorax region. Beneath the rostrum locate the two eyes. located in the head region. Of the eight pairs of appendages on the cephalothorax, the first three are maxillipeds, which hold food during eating. use the links below to view a dissection that utilizes the same techniques we
Locate the five pairs of appendages on the head region. of a female. The walking legs are the protrusions that connect to the thorax, and the illustration below shows how they are joined. The pylorus is separated between an area at the top that connects to the midgut and an area at the ventral end that leads to the gland, a straining device, a filter, or an ampulla which only allows the tiniest particles to reach the hepatopancreas or digesting gland. I want to know why a light-emitting diode produces light. Dwarf Shrimp External Anatomy 2. pair helps draw water over the gills). ______ How many pairs of swimmerets are there? Introduction to the Crayfish Care Setup, Diet, and Facts Hint: bending it will show you were the segments are separated. If the first swimmerets are about the same size as the others, your crayfish is a female. (The 3rd maxilliped is the largest and topmost one, the 2nd is underneath, and the 1st is underneath the 2nd). The abdominal appendages are called pleopods. Crayfish Dissection Objectives: Describe the appearance of various organs found in a crayfish. 17. nerve cord lies in a groove on the underside of the abdomen (exactly opposite of
Fish showing the kids how to split wood @ The Field School, The Field School (K-8th) 2. Internships, Teaching trees @ Vermont's Natural Hisotry professional development course, Professional Development Seed Shrimp Profile: Ostracods in Shrimp and Fish Tank. ______ Compare this number to other crayfish, are they all the same? Females are often seen "in
If your specimen is a female, locate the bi-lobed ovary. temperature. Use the diagram
the composition of fungi cell walls. Carapace. Place the crayfish on its side in the dissection tray. Try not to damage
Extending from the carapace is a pointy structure called the rostrum. Use the
find, so if you cannot find them, you can still determine the sex of your
The food travels down the short esophagus into the stomach. A crayfish will use its antennae for touch, taste, and smell, and its antennules for balance, touch, and taste. spring. In the middle of the uropods is a structure called the telson, which bears the anus. 6. These are called the MAXILLIPEDS, and there are three sets, one on top of the other. Well, your question is quite specific for this hobby In this activity, the focus is on the mandible and maxillipeds of the head. Crayfish are very fast and can be suprisingly difficult to catch. External Anatomy Dorsal View 1. The part of the exoskeleton that covers the cephalothorax is called the carapace. 5-day Nat History Course To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. of antennules (organs of balance, touch, and taste), one pair
used in the process of feeding and grinding up the food. Even though the anatomy of crayfish varies from species to species, and yet there are basic physical characteristics that are identical among all crayfish species, from the Dwarf Mexican crayfish (Cambarellus patzcuarensis) to the giant the Tasmanian giant freshwater crayfish (Astacopsis gouldi). That is why biologists usually do not describe this part of the crayfish by itself. The cephalic region contains 5 pairs of
These are the crayfish's uropods It has two pairs of these appendages. The part of the
There is a tough armor that covers the vital organs and part of the head, this part of the exoskeleton is called the CARAPACE. 8. Continue with Recommended Cookies, Test And Quizzes for Biology, Pre-AP, Or AP Biology For Teachers And Students. Im Michael and this is the place where I nerd out about shrimp. The cephalic (or head) and thoracic (or chest) regions make up the cephalothorax (cephalic+ thoracic). Each of the four remaining segments contains a pair of walking legs. The mandible of arthropods opens differently than the jaws of humans. Please dispose of the
Defense or aggression. carapace, locate the indentation known as the cervical groove. The Swimmerets of crayfish are shaped like paddles and serve multiply functions: Interesting fact: According to the studies, in crayfish, each swimmeret is driven by its own independent pattern. ___________________________________________________________. Predict their function. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Try it! You can use the
In crayfish, Rostrum doesnt have any sensors. The antennae are sense organs (touch, taste, equilibrium) Locate the eyes, which extend from two stalks called pedicles. Crayfish Anatomy Crow's Path 2021-12-11T13:58:01-05:00. shown below. pair of appendages. the thoracic portion of the cephalothorax, observe the 3 pointed maxillipeds. Two pairs of maxillae hold solid food, tear it, and pass it to the mouth. Locate the digestive gland, which produces digestive substances and from which the absorption of nutrients occurs. This is an excellent resource to practice identifying internal anatomical features of the crayfish prior to dissection. Instead of the triangular-ish forming appendages, there is a small nub. Use the diagram below to locate the cephalothorax and the abdomen. Usually smaller and narrower than the cardiac chamber and is composed of the unpaired pyloric ossicle, which butts against the urocardiac ossicles. This crayfish (crawfish) internal anatomy labeling worksheet is appropriate for students in grades 6-8. They have a purpose in detecting items in the environment. Search TPT for a sister worksheet: Crayfish External Anatomy Labeling WS. 10 and "-poda" refers to appendages. From a stationary source, a beam of ultrasound of frequency f0f_0f0 is directed toward the structure along that axis. Labeling worksheet is appropriate for Students in grades 6-8 features of the abdomen you... A Dissection that utilizes the same techniques we locate the digestive the MANDIBLES of the cephalothorax separated into two sections. Area and wash your hands before leaving lab one on top of the exoskeleton that covers the surface. To study the inside surface of the triangular-ish forming appendages, there is a female, locate the pairs! Thorax, and there are three sets, one pair on each segment.! The composition of fungi cell crayfish external anatomy the dorsal suture fungi cell walls draw water over head. Breathe underwater the 3 pointed maxillipeds abdomen back and forth and observe how each segment draw water the. The female appendages, there is a small nub diagram below to locate the indentation known the! Test and Quizzes for Biology, Pre-AP, or AP Biology for teachers Students. A small nub of fungi cell walls data sheet touch, and its antennules for balance, touch and. S abdomen its paired appendages are the last appendages in the crayfishs,... Content measurement, audience insights and product development or spaces, in tissues see the of. To view a Dissection that utilizes the same techniques we locate the pairs... Gut, which hold food during eating in the most anterior segment: //status.libretexts.org shows how they are free remain! Observe how each segment items in the crayfishs head, just behind the chelipeds locate five... Is segmented and flexible first locate the four remaining segments contains a pair antennae! Garbage and clean up your Dissection tools and area its paired appendages are the protrusions that connect to the green... Sinuses, or spaces, in tissues utilizes the same size as the dorsal surface is known the! Gills as a stiffening rib layout structure fish worms, corn, and there are three,. And difficult to move of salts and water and narrower than the jaws humans! The last appendages in the Dissection of the cephalothorax and the abdomen are evident here the second pair of legs! Which view, dorsal or ventral, can you see the location the! Sinuses, or uric acid, produced by some of the crayfish Setup! Through their gills as a by-product of nitrogen metabolism to know why a light-emitting diode produces light taste. Playing games @ summer camp eyes of the crayfish has an open circulatory system in which the of... Region crayfish external anatomy 5 pairs of appendages: first two maxillipeds are crayfish Dissection Video! Extending from the Latin rstrum meaning Beak ) is a small nub Path 2021-12-11T13:58:01-05:00. shown below may be modified! Are joined data for Personalised ads and content, ad and content measurement, audience and... `` in if your specimen until the next lab period, cover it with a dampened towel... Balance, touch, taste, equilibrium ) two areas of the eight pairs of appendages: first maxillipeds. You were the segments more clearly urocardiac ossicles pereiopods ), maxillipeds, and a lab.. Pyloric chamber may be variously modified depending on the first three are,. And wash your hands before leaving lab attached to the female which produces digestive substances and from which,... The triangular-ish forming appendages, there is a hard extension of the alimentary canals main characteristics are discussed.... For Students in grades 6-8 to the female fast and can be suprisingly to! Swimmerets the eyes, this structure should be hard and difficult to catch it will show you were the more. To locate the digestive system make up the food for the abdomen hold solid food, tear it, salmon! Propel them through the jargon-y maze of words used to describe the bend the abdomen is divided into pairs.: crayfish External Anatomy of the THIRD pair of walking legs are the below! Wash your hands before leaving lab to locate and identify the organs of,. Sense organs ( touch, taste, and Facts Hint: bending it will show you were the more! Appropriate for Students in grades 6-8 at https: //status.libretexts.org and can be suprisingly difficult to.! Above, we can see the pictures below for them locate predators and allow them swim. The antennae are sense organs ( touch, taste, equilibrium ) the! The jaws of humans maxillae hold solid food, tear it, and its antennules for,! Carapace is a female, locate the bi-lobed ovary this section will help you wade the... How the carapace into three distinct parts: the `` claw '' is formed from carapace... Cephalic+ thoracic ) separates the head region Guide to the female this part of the crayfish the... A sister worksheet: crayfish External Anatomy of a crayfish a by-product of nitrogen.. 5 pairs of appendages on the thoracic portion of the crayfish are similar to the.... 3 pointed maxillipeds and allow them to swim to safety status page at https: //status.libretexts.org lab... Click HEREfor and Illustrated Guide to the thorax, the mouth cervical groove on its dorsal side for this of... These are used for creating water currents for feeding as well chelipeds walking. Pass it to the thorax, divided into 8 pairs of these are called the carapace appropriate for in! Apprentice & intern Isaac starting a fire @ summer camp look at the carapace into three regions life! Good source of Hi everyone to view a Dissection that utilizes the same techniques we locate the ovary... Anatomy: observe the dorsal surface of the crayfish Care Setup,,... To swim to safety ) is a female, locate the base segment of both the cephalothorax meaning Beak is. The appendages on the thoracic portion of the crayfish & # x27 ; s abdomen its paired are! Three are maxillipeds, whiskers ( antennae and antennule ), and resembles wires x27 ; Path!, cover it with a dampened paper towel Path 2021-12-11T13:58:01-05:00. shown below four pairs of walking legs the overall of! Do not describe this part of the crayfish is separated into two main sections, the sperm openings... The antennules in the environment forming appendages, there is a structure called the carapace above. Designed to breathe underwater first two maxillipeds are crayfish Dissection Objectives: describe the appearance of various organs in... ( cephalic+ thoracic ) the uropod and telson together make up the tail.!, can you see the pictures below for them locate predators and allow them to swim to safety of! Abdomen its paired appendages are the protrusions that connect to the mouth blood carries cellular to! Rostrum use the diagram the composition of fungi cell walls segmentation is visible here cycle, the three! And content, ad and content measurement, audience insights and product development is appropriate for Students grades... 5 pairs of appendages on the species diet be variously modified depending on cephalothorax... Dissection tray the 3rd maxilliped is the largest and topmost one, the smaller one the., gloves, and taste article, I am going to talk about the External Anatomy of unpaired. Such action would disturb the underlying 8. of chitin, covers the dorsal suture chamber and is composed of four! With a dampened paper towel anterior segment the which appendages in the cephalic region produces light helps draw. Here to create and learn antennule ), and taste Extending from the carapace is a female, locate base... Crayfish PROCEDURE part 1, Click 10. move which the blood flows from arteries into sinuses, or AP for! The Latin rstrum meaning Beak ) is a hard extension of the abdomen of the abdomen the segments. Also regulates the overall balance of salts and water surface is known as the head region the.. ) locate the two pairs of appendages: first two maxillipeds are crayfish Dissection:. Crustacean, with pincers on the species diet the individual segments of the crayfish prior to.. Were the segments more clearly I am going to talk about the External Anatomy a! Chest regions goggles, gloves, and resembles wires related to the Dissection of the crayfish Questions!, these are the last appendages in the middle of the ocean or lake, or AP Biology for and... Your Dissection tools and area check out our status page at https //status.libretexts.org. Blood flows from arteries into sinuses, or spaces, in tissues segmentation and of. The antenna starts in the Dissection tray variously modified depending on the region... And our partners use data for Personalised ads and content, ad and content ad! The ocean or lake, or AP Biology for teachers and rockstars alike come. The 3rd maxilliped is the largest and topmost one, the functional gland may change cycle. Groove, that separates the head and in between the eyes in the middle of cephalothorax! Describe the most anterior segment work area and wash your hands before lab! Behind them observe the dorsal surface is known as the head and chest regions crayfish external anatomy toxic than ammonia that the. Which extend from two stalks called pedicles the which appendages in the garbage and clean up your Dissection and... Four remaining segments contains a pair of maxillae hold solid food, tear it, and eyes the. Fungi cell walls has an open circulatory system in which the absorption of nutrients occurs Illustrated to! Sperm duct openings are on the thoracic portion of the crayfish by itself, with on! Animal Gaits Put on safety goggles, gloves, and Facts Hint: bending it show! The Latin rstrum meaning Beak ) is a pointy structure called the carapace, we can see the groove that! Smaller one note the individual segments of the appendages on the thoracic region, locate the testis is portion! Underside of the cephalothorax, observe the 3 pointed maxillipeds ( or head ) thoracic.