CEPHALOPODA. 463 



chiate Cephalopoda the sense of taste is sufficiently acute ; far supe- 

 rior, indeed, to what is enjoyed by any of the Gasteropod Mollusca, 

 and possibly even excelling that conferred upon fishes, and others 

 of the lowest Vertebrata that obtain their food under circumstances 

 such as render mastication impossible, and the perception of savours 

 a superfluous boon. 



(504.) That the Cephalopoda are provided with a delicate sense 

 of smell, and attracted by odorous substances, is a fact established 

 by the concurrent testimony of many authors, although in the most 

 highly organized genera nothing analogous to an olfactory apparatus 

 has as yet been pointed out : nevertheless, in Nautilus, Professor 

 Owen discovered a structure which he regards, with every show of 

 probability, as being a distinct organ of passive smell, exhibiting the 

 same type of structure that is met with in the nose of fishes ; and, 

 from the circumstance of its being the first appearance of an organ 

 specially appropriated to the perception of odours, well deserving 

 the attention of the physiologist. We may here premise, that the 

 exercise of this function in creatures continually immersed in water 

 must depend upon conditions widely differing from those which 

 confer the power of smelling upon air-breathing animals. In the 

 latter, the odorant particles, wafted by the breeze to a distance and 

 drawn in by the breath, are made to pass, by the act of inspiration, 

 over the nasal passages ; and, being thus examined with a minute- 

 ness of appreciation proportionate to the extent of the olfactory 

 membrane, give intimations of the existence of distant bodies 

 scarcely inferior to those obtained from sight and sound. But, in 

 an aquatic medium, information derived from this sense must be 

 restricted within far narrower limits ; inasmuch as the dissemination 

 of odoriferous particles must necessarily be extremely slow, and the 

 power of perceiving their presence comparatively of little import- 

 ance, seeing that the extent to which it can be exercised is so 

 materially circumscribed. Smell, in aquatic animals, is therefore 

 apparently reduced to a mere perception of the casual qualities of 

 the surrounding element, without any power of inhaling odours 

 from a distance. Simple contact between a sufficiently extensive 

 sentient surface, and the water in which it is immediately immersed, 

 is all that is requisite in the case before us ; and if an organ can be 

 pointed out, constructed in such a manner as to adapt it to fulfil 

 the above intention, there can be little hesitation in assigning to it 

 the office of an olfactory apparatus. 



(505.) In Nautilus, the part indicated by Professor Owen* as 



* Loc. cit. p. 41. 



