Habits of the Seal 75 



two zones, as in the Phoca monachus of the Grecian Islands, 

 encircling the globe, of a thinner texture, so much so as to be 

 only one-fourth part of the usual thickness, and more flexible 

 than the rest of the sclerotic coat ; and as the straight and 

 oblique muscles of the globe are inserted anteriorly to these 

 flexible zones into a thicker part of the tunic, it is probable 

 that their simultaneous contraction may alter the length of the 

 axis of the eye, and the form of the transparent cornea, by 

 approaching the latter to the retina, and by rendering it more 

 or less convex, and thus better adapt it to the different media 

 in which the creature lives. I think this the more likely, 

 because I have often observed that seals, on first appearing on 

 the surface of the water, appear somewhat bewildered, and do 

 not distinctly discern objects, till their eyes have had time to 

 adapt themselves to the more rare medium to which they are 

 exposed. 



The nose of the seal is an organ of more perfect formation 

 than that of any other quadruped. The nostrils are most accu- 

 rately closed at the entrance by very perfect valves, to prevent 

 the ingress of water when it dives, and, indeed, at all other 

 times, except when it respires. Its breathing also, at all times, 

 occurs at very irregular intervals, often extending to half a 

 minute between each inspiration, but the quantity of air it then 

 receives is very great. As to the internal formation of the nose, 

 it possesses one of the most beautiful structures which the 

 whole class exhibits, especially from the amazing number of 

 the convolutions of those bones on which the infinite ramifica- 

 tions of the olfactory nerves are spread. It has, indeed, been 

 computed by Sir Busic Harwood, that the smelling surface in the 

 nose of a single seal amounts to the enormous extent of two hun- 

 dred and forty square inches. Now it is no less worthy of remark 

 that something of this curious complication in the organ of 

 smelling likewise obtains in other aquatic animals, and espe- 

 cially the otter, which is a very remarkable circumstance, when 

 we consider that, as before observed, their nostrils, like their 

 ears, are most accurately closed by valves, to prevent the en- 

 trance of the water when they dive, and, indeed, at all other 

 times, except during breathing. A question, therefore, natu- 

 rally arises, — that if, in the pursuit of their prey, or other sub- 



