LIST OF WOODCUTS. 



Fig. 1. Astacus fluvLililis. 



2. 



3. 



4. 



5. 



10. 



11. 

 12. 

 13. 

 14. 

 15. 

 16. 

 17. 

 18. 



Frontispiece. The Common Ckatfish, Astacus fluviatilis, (male) 



Side view of the male. . . 6 



doksal views of male .4nd female 18 



Ventral views of male and female 21 



The gills 26 



Dissection fkom the doesal side 



(male) 28 



Longitudinal vektioal section of 



the ALIMENTAKY CANAL . . 29 



A gastkolith oe "okab's eye" . 30 

 Attach.ment op young to swim- 



meket of mothek . . . 41 

 Steuctuee of the stomach . . 53 

 Longitudinal section of the sto- 

 mach 66 



EooF of the stomach, fkom within 60 



Dissection feom the side (male) . 62 



Alimentaet canal feom above . 65 

 Blood coepuscleS . . . .68 



Tkansverse section of thokax .. 70 



The heaet . . . 72 



Steuctuee of the gills . . 76 



The geeen gl.ind .... 83 



