498 Mr. Garner on the Nervous System of Molluscous Animals. 



circle then is double inferiorly, as we saw so low in the scale as in Conchifa-a, 

 and the anterior division supplies, as in them, the organs of locomotion, and 

 the posterior, the branchiae, &c. In conjunction with the siphonic nerves 

 arises on each side a nerve (3/.), which pierces the cranium and enters the 

 orbit, supplying two small muscles of the eye, of which one unites with its 

 fellow of the opposite organ, and the conjoined tendon slides backwards and 

 forwards in a pulley on the anterior and superior part of the cartilage. The 

 branchio-visceral nerves descend on each side of the vena cava, giving many 

 nerves, and amongst others, many filaments (t.) to the oesophagus, joining 

 those from the pharyngeal ganglia. It divides behind the rectum, a branch 

 going outwards to the base of the gill (?<.), forming there an oblong gan- 

 glion (F.), aud supplying that organ, &c.; minute filaments go to the peri- 

 cardium and heart; the remaining branches get upon the oesophagus (0'.), 

 and with those previously described, form a large ganglion (G.), in the Sepia 

 a quarter of an inch in its long diameter, upon the stomach, between the 

 cardiac and pyloric orifices. From this sympathetic ganglion filaments of a 

 large size go to the caecum (v.), intestine, ink-duct, penis and oviduct (w.), 

 meeting filaments from the branchio-visceral. The nerve of the mantle gives 

 a few nerves to the muscles, pierces the pillars supporting the head, divides 

 into two branches, of which one forms the great ganglion (H.) of the mantle, 

 from which nerves i-adiate in every direction to that part. The other continues 

 to descend, receiving a large nerve from the ganglion, and then gets behind 

 the large longitudinal cartilage, supporting the fin, where it subdivides, supply- 

 ing that organ with large nerves (z.). Before it has pierced the muscle this 

 nerve gives off fine filaments, which, running along the hepatic artery, get upon 

 the oesophagus, and mix with its other filaments derived from other sources. 



All the Cephalopoda*, perhaps, have acoustic vestibules, containing a bag of 

 fluid on which the nerve ramifies ; also a small calcareous body, which in the 

 Sepia has an accidental resemblance to the human incus. 



In the eye there is a nervous coat or retina behind the pigmentum nigrum ; 

 and it has been a problem how it could be affected by light. The author is 



* Not, however, according to Mr. Owen, in the Nautilus. The author has not seen them in the 

 Sepiola, where the cranium is membranous ; but probably it has been concealed, from its small size, 

 in the latter. 



