302 



THE CEPHALOPODA 



Rossia and Sepia, but are much more intimately united in Sepiola, 

 and are almost entirely fused together in Spirula (in which genus 



FIG. 268. 



Spirula, a nearly median sagittal section, seen from the left side, a, anus ; ar, arms ; a./, 

 aboral fossa ; b.d, bile-duct ; c.c, cephalic cartilage ; c.g, cerebral ganglion ; d.m, dorsal man- 

 dible ; f.c, funnel collar ; fi, fin ; fu, funnel ; i.b, ink-bag ; li, lip ; liv, liver ; ma, mantle ; ma', 

 shell secreting part of the mantle ; oe, oesophagus ; o.g, optic ganglion ; ot, otocyst ; pa.c, 

 pallial cavity; p.g, pedal (brachial) ganglion ; pn, "pancreas"; p.s, pyloric sac; ra, radula ; 

 s.g, salivary gland ; sh, shell ; si, shell siphuncle ; sp, last septum of the shell ; st, stomach ; 

 t, tentacular arm ; t.d, pallial terminal disc; to, tongue; v.m, ventral mandible; v.n, visceral 

 nerve ; w.b, white body. (After Huxley and Pelseneer.) 



the liver is partly contained in the last chamber of the shell, Fig. 

 268, liv), in Onychoteuthis, Ommatostrephes, Loligo, and the Octopoda, 

 with the exception of Argonauta. In these last cases the liver 



