432 



ARTUROPODA. 



by numerous blood-vessels. In Birgus latro the gill chamber is 

 divided into two portions (fig. 438), the npj^er part being pulmo- 

 nary, the lower containing the reduced gills. 



Fig, 



438.— Diagrammatic sectiuri through Birgus latro, ghowinfc lungs. (From Lang, 

 after Semper.) Oj, a^, afferent blood-vessels; ah, pulmonary chamber: tk\ el, el', 

 efferent blood-vessels ; h, heart ; k, gills ; led, branchiostegite ; j-', pericardium. 



Fio. 439.— Anatomy of Crayfish Ll.'imi'iK). ,-1, dorsal surface removed: B, scheme 

 ot circulation ; C, viscera removed, showins green gland and nervous system, a, 

 anus; rtr,, hepatic artery; nc, antenna ; <„, antennula, also sternal artery; am, 

 muscles of stomach; <ro ophthalmic artery ; »/7, abdcuninal artery; or, ventral 

 Sl^i"^^ ' i' i'"""!'^', "'"'''', ^'r' *^''^ arteries; e, oesophageal commissures; orf, 

 green gland ; ,;» lirain ; ,,u^-'\ ganglia of ventral cliain : h, heart ; lul, intes- 

 tine ; fc, inandiliular mnscles; /, /', liver and its duct; hi, stomach; o, otocvst : 

 oes, aj.sopbagus ; .)» optic nerve ; pi; pericardium ; s,ni, sympathetic nerve ; t, f, 

 unpaired and paired portions of testes ; v, ventral blood sinus ; cd, vas deferens ; 

 vdr, vems from gills to heart. 



