28 





 REPRODUCTIVE SYSTEM 



FIG. 5. MALE ORGANS detached (seen in situ PI. XIII. fig. 2) 

 Testes, make spermatozoa. 



Yas 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 parent. 

 Albumen. 



Vitelline membrane. 

 ViteUus. 

 DEVELOPMENT 



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



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



FIG. 8. Adult Crayfish showing appendages. 



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



