MI 



PTIYLUM MOLLUSCA 



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. 



iiifca.rt 



Fn.. i'ii;-2.— Sepia cultrata, mala specimen seen from the postero-ventral aspect, the mantle- 

 cavity opened as in Fig. 058, the posterior body-wall partly dissected off, so as to expose tho 

 organs in the visceral sac, the ink-sac and duct removed, aort. main aorta ; aort.' aboral 

 aorta ; app. appendage of left branchial heart ; cier. cajcum ; inf. cart, funnel cartilages ; tiv. 

 digestive gland ; I. alul. r. left abdominal vein ; /. njt'. br. left afferent branchial vessel ; I. ottn 

 left auricle ; /. br. ht. left branchial heart ; I. ct>n. left ctenidium ; t. st. </. left stellate 

 ganglion ; mant. cart, mantle-cartilage ; mo. mouth ; pen. penis ; pro**, prostate ; r. aljd. r. 

 right abdominal vein ; r. rten. right ctenidium ; rect. rectum ; r. ven. a/*;), appendages of 

 right afferent branchial vessel ; te. testis ; tc. v. vein to testis ; ra. valve of funnel ; rent. 

 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 pleuro-visceral ganglia (Fig. 666), all of 

 relatively large size, are closely aggregated together around the 



3 c 2 



