710 



ZOOLOGY 



SECT. 



FIG. 626. Triton rubicundus. Nervous system, from the dorsal side. 

 cer. buc. con. cerebro-buccal connective ; cer. g. cerebral ganglion ; col. 



mantle-nerve ; opt. n. optic nerve ; ped. con. cerebro-pedal and pleuro- 

 pedal connectives ; ped. g. pedal ganglia ; pi. g pJeural ganglion ; r. 

 abd. g. right abdominal ganglion ; r. br. n. right branchial nerve; r. buc. 

 gang, right buccal ganglion ; r. mant. n. right mantle-nerve ; supra, g. 

 supra-intestinal visceral ganglion ; tent. n. nerve to tentacle vise n 

 visceral nerve-branches. 



parent, mem- 

 brane the peri- 

 car dial mem- 

 brane. The heart 

 consists of two 

 chambers, an 

 auricle (Fig. 623, 

 aur.) and a ven- 

 tricle. The 

 auricle, which is 

 the smaller of the 

 two, is situated 

 somewhat in 

 front of the 

 ventricle, close 

 to the ctenidium, 

 from the main 

 central vessel of 

 which it receives 

 the blood. The 

 ventricle (vent.) 

 is of somewhat 

 pyramidal shape, 

 but with the 

 edges rounded 

 off. Its wall is 

 extremely thick 

 and muscular. 

 Passing out from 

 the ventricle 

 towards the right 

 is a thick artery, 

 which soon 

 divides into two, 

 one running for- 

 wards, the other 

 backwards the 

 anterior (ant. 

 aort.) and pos- 

 terior (post, aort.) 

 a o r t CB. The 

 former is a very 

 large trunk which 

 runs forward s 

 below the pos- 

 terior oesopha- 

 gus, crop, and 



