28 



Reproductive System — 



i'lG. 5. !Maxe Oeoans detached (seen m situ PI. XIII. fig. 2) — 

 Testes, make spermatozoa. 



Vas deferens, tube for conveying spermatozoa out of body. 

 Spermatozoon, cilia absent. 

 DiAG. 3. Ovum of Crayfish just hatched — 



Outer and inner membranous coats produced at one point into a process for attachment to the 



body of paiunt. 

 Albumen. 



Vitelline membrane. 

 Vitellus. 

 Development — 



Fig. 6. Young Lobster as it emerges from egg, a zo'ea which passes by metamorphosis into adult form. 



Fig. 7. Young Crayiish as it emerges from egg, essentially similar to adult, no zoea stage. 



Fig. 8. Adult Crayfish showing appendages. 



Fig. 9. Limbs used for masticatory purposes, laid out. 



