I. CRUSTACEA: DECAPODA 

 ,cf, Ct, Cc,, 



379 



Fig. 399. — Diagrammatic section through Birgiis lairo, shomng lungs (from 

 Lang, after Semper). Uj, a,, afferent blood-vessels; ah, pulmonary chamber; ek, el, el', 

 efferent blood-vessels; h, heart; k, gills; kd, branchiostegite; p. pericardimn. 



31,... 



Fig. 400. — Anatomy of Crayfish (.4 rfoctw). ^ , dorsal surf ace removed , B scheme 

 of circulation; C, viscera removed, showing green gland and nervous s\stem a anus; 

 aa, hepatic artery; ae, antenna; ai, antennula, also sternal arterv'; am, muscles of 

 stomach; ao, ophthalmic arter)'; ap, abdominal arter}'; aii, ventral arterj-; hi, urinary 

 bladder; br, gill arteries; c, cesophageal commissures; gd, green gland; gn', brain; 

 JH"-'^, ganglia of ventral chain; h, heart; hd, intestine; k, mandibular muscles; /, /', liver 

 and its duct; m, stomach; 0, otocyst; oes, oesophagus; on, optic nerve; pc, pericardium; 

 sgn, sympathetic nerve; t, f, unpaired and paired portions of testes; v, ventral blood 

 sinus; vd, vas deferens; vbr, veins from gills to heart. 



