XTI 



PHYLUM MOLLUSC A 



767 



axial canal being left through which the water penetrates freely to 

 all parts of the gill. The blood carried to the gill by the afferent 

 branchial vessel passes in a system of minute branches through 

 the lamellae, and is gathered up again into vessels which open into 

 the main efferent vessel leading to the auricle. 



inf.ca.rt 



te* 



Fit;, t'iii'2. Sepia cultrata, male specimen seen from the postero-ventral aspect, the mantle- 

 cavity opened as in Fig. iwS, the posterior body-wall partly dissected off, so as to expose the 

 organs in the visceral sac, the ink-sac and duct removed, aorl. main aorta; nori .' altornl 

 aorta; o/*y). appendage of left branchial heart ; ceec. rn-rum ; inf. <',/. funnel cartilages; /"'. 

 digestive gland ; (. all. >-. left abdominal vein ; I. a.ft'. iir. left afferent branchial vessel ; /. aur. 

 left auricle; 1. l>r. Jtt. left branchial heart; I. ct<.n. left ctenidiuni ; I. */. </. left stellate 

 ganglion; mnnf. cart, mantle-cartilage; mn. mouth; / ii. penis; pros. prostate ; r. //. v. 

 right abdominal vein; r. <-te,i. right ctenidiuni; r-t. rectum; r. ven. "/>/>. appendages of 

 right afferent branchial vessel; l<-. testis ; tc. r. vein to testis ; m. valve of funnel; /<;*/. 

 ventricle. 



Nervous System. --Though parts homologous with those 

 of Triton are recognisable in the nervous system of Sepia, their pro- 

 portions and arrangement indicate a higher grade of organisation. 

 The cerebral, pedal, and plcuro-visceral ganglia (Fig. 666), all of 

 relatively large size, are closely aggregated together around the 



3 c 2 



