38 



CRUSTACEA 



Xt'-J 



Fig. 1. — Astacus fluviatilis. A male specimen, with the roof of the cara- 

 pace and the terga of the abdominal somites removed to show the viscera 

 (natural size) : aa, Antennary artery ; ag, anterior gastric muscles ; amm, 

 adductor muscles of the mandibles ; cs, cardiac portion of the stomach ; 

 gg, green glands; h, heart; hg, hind gut, or large intestine ; Lr, liver ;_oa, 

 ophthalmic artery; pg, posterior gastric muscles; saa, superior abdominal 

 artery; t, testis; vd, vas deferens. (Huxley.) 



(c) Openings — how many? Use? 



(d) Trace small white tubes, arteries, to different parts 



of the body. 



