636 



SEAL. 



animals which have much action in walking, running, 

 and leaping. The ribs are fifteen on each side, ten 

 true ones, and five false. The sternum is made up 

 of eight pieces of bone nearly straight, and the last 

 one longer than any of the others. The neck of 

 course has the normal number of seven vertebra ; 

 and there are fifteen dorsal ones for the articulation 

 of the ribs. There are five lumbar vertebrae, with 

 very short processes, four sacral ones, and twelve 

 caudal. The pelvis is long and straight, and the os 

 pubis is articulated in nearly the same manner as in 

 man. There are no clavicles, so that the animals 

 have no cross motion of the fore paws, and cannot 

 use them as claspers in the way that they are used 

 by the whale. The head of the humerus is well 

 formed, and that bone itself is longer than the cor- 

 responding bone of the posterior extremity. The 

 bones of the fore-arm are very dark, and the carpus 

 and tarsus consist each of seven bones. 



Of the senses of the seals, it is difficult to speak 

 with much precision. Their sight is probably the 

 most acute of the whole, and the one upon which 

 they have their chief dependence in the finding of 

 their food. On land they are, as we have already 

 said, quick of hearing ; but how and to what extent 

 that sense may serve them under the water it is not 

 easy to say ; but from the structure of those parts 

 which are considered as the organs of hearing in 

 fishes, it is difficult to draw any conclusion as to how 

 the ear of the seal, being as it is, a quick ear on land, 

 may be useful to it when under water. We must, 

 however, just notice the organs. 



In respect of the sense which is called touch, and 

 which appears to be composed of the sensitiveness 

 of the surface of the body and of the muscular sense 

 jointly, the seals must be dull. None of their extre- 

 mities, or indeed any part of their skin, can be looked 

 upon as the peculiar seat of such a sense ; and sensi- 

 bility of the skin would be a very inconvenient faculty 

 in animals which are exposed to so great alternations 

 of temperature as the seals experience in their ordi- 

 nary habits. In their transitions from water to land 

 and the reverse, they do not appear to feel the least 

 uneasiness ; and in the polar seas they do not appear 

 to be in the slightest degree affected by the utmost 

 rigour of the atmosphere, or the most rapid passage 

 from one extreme of temperature to another. It does 

 not appear that the hairs upon them are, in the ge- 

 neral covering of the body, possessed of the same 

 degree of sensibility as the hairs of land mammalia. 

 Many naturalists have, however, come to different 

 conclusions respecting the long bristles, or whiskers, 

 which are near the mouth. These are, in some of 

 the species, jointed, or formed with nodosities, some- 

 thing resembling those of the antennae of some beetles. 

 They have their roots in a sort of cylindrical capsule 

 of horny consistency at the bottom, and meeting 

 there with some small vessels connected with the 

 muscles, and also with a fine membrane, which lines 

 the whole of their internal surface ; and the opinion 

 is, that the bristles are, through the medium of this, 

 a sort of organs of touch. These bulbous roots of 

 the bristles, especially in the fine membrane with 

 which they are lined, are closely connected with 

 many ramifications of the second principal branch of 

 the fifth pair of nerves ; and this is another reason, 

 and rather a powerful one, for concluding that they 

 are organs of touch : the more so that it is pretty well 

 ascertained that the whiskers of all land animals 



which have such appendages in the form of bristles 

 are of this description. But still, when the seals are 

 in the water we cannot suppose that the sensations 

 communicated by means of their bristles can be very 

 acute. 



The tongue of the seal is much better adapted for 

 being an organ- of taste. In the common seal it is 

 about three inches long, and one inch and three 

 quarters broad at the base. The os hyo'ides, or base 

 of the tongue, is well formed, and amply supplied 

 with muscles. In that species, and also in most of 

 the others, it is cleft at the point, furrowed in the 

 posterior part, and beset with papillae of different 

 sizes, which are understood to be the proper organs 

 of taste. 



The sense of smelling is much less perfect than in 

 the land carnivora ; and to have given this sense in 

 any very high degree would have been giving a 

 power which would have been of comparatively little 

 use to the animals in that part of their personal 

 economy in which alone senses are required, namely, 

 the finding of their food. The nostrils are also shut 

 when the seal is in the water, and there are two 

 rather powerful muscles which work them ; the one 

 has its origin in the upper jaw-bone and the bone of 

 the nose, and, proceeding obliquely downwards, is 

 inserted in the " wing," or external and flexible lobe 

 of the nostril. When it contracts, it of course 

 distends the opening of the nostril ; and when it 

 relaxes, it allows that to be closed, so as completely 

 to exclude the water. The other muscle, which is 

 considerably thicker and stronger than this one, has 

 its origin in the upper jaw-bone, near the alveole of 

 the teeth ; it passes along the substance of the upper 

 lip, forming a plexus, in which the bulbs of the hairs 

 of the whiskers are included, and then it is inserted 

 on the inner surface of the wing of the nostril ; so 

 that, when it contracts, the nostril is closed with con- 

 siderable force. It is often said in the books that 

 there is a valve for closing the nostril of the seal, but 

 there is no valve save the flexible edge of the nostril 

 itself, which is worked by its muscles in the manner 

 that we have described. 



Of the hearing of the seals we have already 

 spoken. Their internal ears have nothing very par- 

 ticular in their structure, and are tolerably well 

 developed ; and the presence or the absence of the 

 external concha, though it of course modifies the 

 hearing, and the distance at which the animal can 

 hear, does not appear to be a matter of the very first 

 importance. 



Sight is, as we have said, obviously the leading 

 sense in these animals, and therefore the eye merits 

 more of our attention. It is an eye fitted for a 

 double purpose or action ; that is, it has habitually 

 to be exercised in the water in the general economy 

 of the animal ; and it also has to act occasionally in 

 the air. There is no eye which can be said to have, 

 upon the whole, to perform both these offices so 

 equally. The eyes of the whales, though no doubt in 

 part fitted for seeing in the water, are very secondary 

 organs in the economy of these animals, as they do 

 not guide them to their ordinary prey, and cannot do 

 so, from the particular situation which they have in 

 the head. The eyes of the otters, also, are used in 

 the water, but always at small depths, where there \9 

 abundance of light, and where any terrestrial, or 

 rather aerial eye, could see perfectly well as long as 

 its owner could remain below the water. The seals 



