34 INVERTEBRATE ZOOLOGY 



Exercise 12. The two pairs of delicate appendages in front of 

 the maxillipeds are the maxillae ; they are cephalic append- 

 ages. Remove with forceps the right-hand second maxilla 

 and draw a large outline of it. The protopodite is wide 

 and leaf-like ; the endopodite is small ; the exopodite is 

 wide and with. the epipodite forms abroad plate, called the 

 scaphognathite, which is used by the animal to maintain a 

 current of water from the gill-chamber. 



Exercise 13. Remove carefully and draw the right-hand first 

 maxilla. The protopodite is wide and leaf -like and similar 

 to that of the second maxilla ; the endopodite is extremely 

 small ; the exopodite is wanting. 



Exercise 14. Extract with strong forceps and draw the right- 

 hand mandible. The biting portion of it, together with 

 the first joint of the small palp, forms the protopodite ; the 

 two terminal joints of the palp are the endopodite ; the 

 exopodite is wanting. Close to the posterior surface of 

 the mandibles are the delicate paragnatha. 



Exercise 15. Remove at its base and draw the right-hand second 

 (the longer) antenna. The exopodite is a short, stiff, plate- 

 like expansion ; the endopodite is the long slender terminal 

 portion. 



Exercise 16. Remove and draw the right-hand first antenna, or 

 antennule as it is also called. No exopodite and endopo- 

 dite are present in this appendage throughout the Crustacea, 

 there being typically but one terminal branch. In the cray- 

 fish and lobster this terminal branch is double. 



Exercise 17. Construct in your notebook a table showing the 

 relation of the appendages and somites, as follows: 



