Mr. Garner mi the Nervous System of Molluscous Animals. 495 



nected by long nerves to the brain. In Buccinum, the two pharyngeal ganglia 

 can be seen to have a root both from the superior and from the inferior portions 

 of the brain. The penis in the male receives twigs (r.) from the cerebral por- 

 tion near the optic. 



The author need not add his testimony to that of Stiebel, Miiller and 

 Blainville as to the real dioptrical structure of the eyes of these animals, and 

 consequently to their being real visual organs, and not (as has been argued by 

 Home) organs of ordinary sensation. No acoustic organ has ever been shown 

 to exist, though it appears probable from experiment that there are such, and 

 that they might be discovered in large foreign species of Gasteropoda. 



The author can only refer the reader for the description of the nervous 

 system in the Pteropoda and Heteropoda, to the works of Cuvier and Poli ; 

 but he may observe, that in both these divisions it appears to be scarcely as 

 perfect as that of some of the lower Gasteropoda, to which it offers most re- 

 semblance, being far below that of the Cephalopoda. 



The nervous system of the Cephalopoda, on one side very similar to that of 

 the Gasteropoda, approaches on the other that of some fishes. It may also be 

 mentioned that the cartilaginous parts or skeleton offers a greater resemblance 

 to the skeleton of a fish than has been supposed. In the Sepia, for instance, 

 (excluding the shell of the back from our consideration,) we see a large cere- 

 bral cartilage surrounding the brain, supporting the eyes, and presenting a 

 number of foramina for the passage of nerves and vessels. There are other 

 cartilages dependent upon this, two articulated with each orbital process, and 

 another at the base of the anterior feet. There are five lengthened cartilages, 

 of which one is anterior to the liver, two lateral, descending from the cartila- 

 ginous disk at the back of the neck, and two others, external to the last, at 

 the base of the fins. These, according to Cuvier, are a rudiment of a spine. 

 In Loligo there is some appearance of this spinal rudiment being articulated ; 

 and it may be mentioned that the vertebrae of some fishes are more or 

 less anchylosed. The structure of the fins offers considerable resemblance 

 to that of those organs in cartilaginous fishes, in the skate, for instance. 

 The muscular fibres are regularly interspersed by long slender cartilagi- 

 nous lamintE, arising from a ridge on the longitudinal cartilage. There are 

 other cartilaginous part.s, which may be rudiments of shoulder-bones, if 



