LIST OF WOODCUTS, 



The Common Ceayfish, Astacus fluviatilis, (male) 



Side view of the male. . . 6 



Dorsal views of male and female 18 



Yentral views of male akd female 21 



The gills 26 



Dissection from the dorsal side 



(male) 28 



Longitudinal vertical section of 



the alimentary canal . . 29 



A gastrolith or ** crab's eye'* . 30 

 Attachment of toung to swim- 



meeet of mother . . . 41 

 Structure of the stomach . . 53 

 Longitudinal section of the sto- 

 mach 56 



EooF OF the stomach, from within 60 



Dissection from the side (male) . 62 



Alimentary canal from above . 65 



Blood corpuscles .... 68 



Transverse section of thorax .. 70 



The heart . . . 72 



Structure of the gills . . 76 



The green gland .... 83 



