Crayfish Anatomy Quiz

1. Which shorter sensory appendages near the front of the head help detect dissolved chemicals and changes in balance?

2. A student identifies several leglike appendages surrounding the mouth that help handle and position food. What are they?

3. Small paired appendages appear in rows along the underside of the abdomen. They can help move water, assist swimming, and, in females, carry eggs. What are they?

4. Starting at the pointed front of a crayfish and tracing the dorsal body toward the rear, which sequence is correct?

5. At the rear of a crayfish, which paired broad appendages form the outer sections of the tail fan?

6. During feeding, which hard, jawlike mouthparts perform much of the crushing and grinding?

7. Which external structures are mounted on movable stalks and provide a broad field of vision?

8. Behind the enlarged chelipeds, a crayfish has slimmer thoracic appendages that support it as it crawls along the bottom. What are these appendages?

9. A student observes a hard, shield-like covering over the dorsal and lateral surfaces of the cephalothorax. Which structure is being observed?

10. While viewing a crayfish from above, you notice a pointed projection extending forward between the eyes. What is it?

11. A crayfish reaches toward an obstacle with its longest slender sensory appendages. Which structures is it using?

12. Which major body region lies behind the cephalothorax and is visibly divided into movable segments?

13. What is the name of the crayfish body region formed by the fused head and thorax?

14. Which unpaired central structure sits between the left and right uropods at the end of the abdomen?

15. A crayfish rapidly flexes its abdomen and pushes against the water using the telson and uropods together. What combined structure are these parts forming?

16. Which paired appendages bear the large claws most directly used for grasping food and defense?