236 



ANIMAL BIOLOGY. 



[Part II. 



and foliaceous. It is well to cut off the branchiostegite before 

 removing the appendages. 



The typical appendage consists of a basal part, or protopodite, 

 from which arises an inner part or limb, the endopodite, and an 

 outer part or palp, the exopodite, and a gill-bearing part or epi- 

 podite. In the legs, forceps, and second and third maxillipeds, 

 the protopodite and endopodite together form a series of seven 

 joints, two of which may, however be coalescent. The student 



FIG. 74. CRAYFISH APPENDAGES. 



A. Second maxilliped. B. First maxilliped. C. Mandible. D. Antenna. 

 E. Antennule. F. Eye-stalk (ophthalmite). G. Swimmeret. H. Twentieth 

 appendage. I. Chela, opened to show processes for attachment of muscles. 

 K. Microscopic section of exoskeleton. 



en. Endopodite. ep. Epipodite. ex. Exopodite. pr. Protopodite. 

 1. Coxopodite. 2. Basipodite. 3. Ischiopodite. 4. Meropodite. 5. Carpo- 

 podite. 6. Propodite. 7. Dactylopodite. 



In I. a&. Process to which abductor muscle is attached, ad. Process to 

 which adductor muscle is attached, h. Hinge. 



-ec. Ectostracum. end. Endostracum. ep. Epiostracum. 



should carefully study and draw the appendages. With the 

 aid of the diagrams in Fig. 74, he will be able to trace the 

 homologies of the parts. In the diagrams the seven joints are 

 numbered. They are named 1. coxopodite; 2. basipodite ; 

 3. ischiopodite ; 4. meropodite; 5. carpopodite; 6. propodite; 

 7. dactylopodite. 



