CEPHALOPODA. 351 



to the parietes of the gizzard in the interspace between the pyloric 

 and cardiac orifices. 



With respect to the parts of the brain in the Vertebrata, which are 

 represented by the cephalic nervous masses in the Dibranchiate * 

 Cephalopods, we may regard the cordiform supei'ior mass, which is 

 principally in communication and coexists with the large and complex 

 eyes, as the homologue of the optic lobes ; it cannot be the cere- 

 bellum, as Cuvier supposed, for that body never gives origin to any 

 nerve ; the cerebellum is also less constant than the optic lobes of 

 the Vertebrate brain, and is posterior to them in both position and 

 order of development. 



The smaller supra-oesophageal mass, anterior to the optic lobes in 

 the Octoptis and some other cephalopods, may represent an olfactory 

 lobe, or the rudiment of a true cerebrum. I have already indicated the 

 parts which seem to represent the crura of the cerebrum ; they unite 

 with that large subcesojihageal nervous mass, which, since it gives 

 origin to the brachial nerves or the analogue of the fifth pair, to the 

 acoustic and respiratory nerves, and to those two large moto-sensory 

 columns which so obviously represent, by their structure, position and 

 distribution, the spinal chord of the Vertebrata, must be regarded as 

 the representative of the medulla oblongata: it is obviously the part 

 of the nervous centre which is most intimately connected with the 

 vitality of the animal, and which is therefore here, as in the higher 

 animals, the deepest seated and best protected part of the nervous 

 system. 



The integument is remarkable in several of the naked Cephalopods 

 for its irregular surface, which seems designed to increase its natural 

 sensibility ; in some, it is provided with flattened processes with den- 

 ticulated margins ; in others, it is beset with branched papillae ; in a 

 third with simple obtuse papillae ; in a fourth with pointed tubercles ; 

 all which projections may serve to warn the animal of the nature of 

 the surfaces with which it may come into contact. The margins of the 

 acetabula and the attenuated flexile extremities of the arms which 

 support them doubtless possess a delicate sense of touch. The 

 fringed circular lip presents another example of the dermal covering 

 modified to be the seat of this sensation. 



The tongue is as highly developed for the exercise of the sense 

 of taste in the dibranchiate Cephalopods as in the Nautilus. 



The external circular lip may probably be the seat of the sense of 

 smell ; it is the part which is most analogous in position and struc- 

 ture to the olfactory laminae in the Nautilus. This sense has been 

 attributed to the Cephalopods by all naturalists who have observed 

 their habits from Aristotle to Cuvier. It appears that the ancient 



