23 8 • ELEMENTARY BIOLOGY. [CIL\r. 



apparatus is spinous and recurved at the tips, 

 for purposes of attachment to the parent. 



y. The abdomen ; fully segmented and terminating 

 in the telson. Four pairs of appendages are 

 alone free, the first and last pairs being buried 

 beneath the larval integument. 



e. Look for and examine stages intermediate between 

 c and d. 



/. The larz'al Lobster, when about half an inch in 

 length. Obtain if possible a specimen in which 

 the abdominal appendages are first appearing. 

 Compare generally with the Crayfish larva and note 

 especially — 



a. The exoskeleto7i ; like that of the Crayfish larva, a 

 continuous uncalcified cuticle. 



(i. The carapace; terminating in front in the ros- 

 trum, which assumes the form of an immense 

 protective spine. 



y. The abdomen; fully segmented and bearing several 

 smaller protective spines. 



8. The eye; its great size at this stage. 



€. The an fen nary orga?is ; both are short and com- 

 pletely under protection of the rostrum. 



^. The thoracic appendai^es. The third maxillipede, 

 great chela and ambulatory appendages, are more 

 nearly uniform in size than in the adult ; they 

 all bear well developed exopodites. 



g. Remove the second ambulatory appendage and 

 the swimmeret of the third abdominal somite. 

 Examine them side by side, and note in both — 



