Fishes. 



6457 



ments of a fish, not of a reptile ; and if we institute a comparison, in 

 this respect, between the mud-fish and those lethargic amphibians, 

 with which it has been more especially associated, the contrast 

 becomes still more striking. 



From the actions of the living animal, let us now proceed to con- 

 sider its structure. In the first place, the limbs of all reptiles, in- 

 cluding the batrachians, are used as levers for propelling forwards a 

 body which rests on the ground ; hence there is always a prominent 

 elbow giving to the creature a most ungainly aspect in walking : now 

 the limbs of the Lepidosiren are represented as being used as perpen- 

 dicular props to support the body clear of the ground when at rest in 

 the water. We can have no reason whatever to doubt the accuracy 

 of the observations I have cited or the beautiful drawing of Mr. Ford, 

 but we cannot fail to observe, that the action and position thus de- 

 scribed and indicated, are those of a fish, not those of *a reptile. 

 We must also consider what is the composition of these tendrils : each 

 is composed of a single bone clothed with skin, which throughout its 

 length is produced into a thin membranous wing, the bone itself 

 being composed of from thirty to forty minute joints, exactly similar 

 to those which constitute the soft rays of malocopterygian fishes, and 

 totally different from the bones which compose the limbs of 

 amphibious or oviporous animals. 



A second external character of importance is, the position of 

 the nostrils ; these are placed on the under side of a slightly 

 projecting snout, as in the cartilaginous fishes, and not all in front, as 

 in the amphibians : the very important question, whether these 

 nostrils are olfactory organs, mere blind sacs as in fishes, or respi- 

 ratory organs communicating with lungs, as in reptiles, has yet to be 

 decided. Professor Owen, after the most elaborately careful dissec- 

 tion, declares them blind sacs ; and the living animal proves they are 

 olfactory organs of great power, since, as Mr. Bartlett and all other 

 observers declare the animal seeks its food by scent, and not 

 by sight. Dr. Gray, but apparently without having made the 

 dissection, states that each nostril has an opening within the mouth, 

 and that a probe may be passed from the external to the internal 

 opening. In this instance I cannot courteously discard either asser- 

 tion ; but it must at once strike the naturalist that one or other of the 

 statements is erroneous, and the tendency will be to agree with that 

 which is based on dissection, and which corresponds with every act 

 of the living animal. Dr. Gray's belief that the mud-fish respires 

 XVII. U 



