146 



MAMMALIA. 



capacious mouths, a great volume of water, there required to he some method of getting rid 

 of it ; and accordingly it passes through the nostrils by means of a peculiar disposition of the 

 velum palati, and is accumulated in a sac situated at the external orifice of the cavity of the 

 nose, whence, by the compression of powerful muscles, it is violently expelled through a 

 narrow aperture pierced on the summit of the head. It is thus that these animals produce 

 those jets of water observed by mariners at so great a distance. Their nostrils, continually 

 bathed in salt water, could not be lined with a membrane sufficiently delicate to enable them to 

 perceive odours; hence they have none of those projecting lamina? observed in other animals : 

 the olfactory nerve is in some wanting, and if there be any endowed with the sense of smell, 

 it must be in a very slight degree. Their larynx, of a pyramidal form, penetrates into the 

 posterior portion of the nostrils, to receive air and conduct it to the lungs, without the animal 

 being obliged to raise its head and throat above water for that purpose : there are no pro- 

 jecting lamina? in the glottis, and the voice is reduced to simple bellowing. They have no 

 vestige of hair*, but the whole body is covered with a smooth skin, under which [or more 

 strictly, forming part of it,] is that thick layer of blubber abounding in oil, the principal 

 object for which they are pursued. 



The mamma: are placed near the anus, and their swimming-paws are incapable of 

 grasping. 



Their stomach has five and sometimes as many as seven distinct sacs ; instead of one single 

 spleen, they have several, that are small and globular. Those species which have teeth have 

 them all conical and similar to one another ; for they do not chew their food, but swallow it 

 rapidly. 



Two little bones suspended in the flesh, ueai the anus, are the sole remaining vestiges of 

 posterior limbs. 



Several have a vertical fin on the back, composed of a tendinous substance, but unsup- 

 ported by bone. Their eyes, flattened in front, have a thick and solid schlerotica ; and the 

 teguments of the tongue are soft and smooth. 



They may be subdivided into two small tribes : those in which the head bears the usual 

 proportion to the body, and those in which it is immoderately large ; the first comprehending 

 the Dolphins and the Narwhals. 



The Dolphins (Delphinus, Lin.) — 

 Have teeth in both jaws, all simple, and nearly always conical. They are the most carnivorous, and, 

 in proportion to their size, the most cruel of their order. There is no ccecinn. 



The Dolphins, properly so called, {Delphinus, Cuv.) — 

 Have a convex forehead, and the muzzle, which forms a kind of beak in front of the head, more 

 slender than the rest. 



The Common Dolphin (D. delph'm, Lin.). — The beak-like snout depressed, and armed on each side of both jaws 

 with from forty-two to forty-seven slender, curved, and pointed teeth : it is black above, white below, and eight or 

 ten feet in length. This animal, found in vast herds in every sea [?], and celebrated for the velocity of its move- 

 ments, which sometimes precipitate it on the decks of vessels, appears really to have been the Dolphin of the 

 ancients. The entire organization of its brain would seem to indicate the docility which they attributed to it.f 



The Great Dolphin (D. tursio, Bonaterre.) — The beak short, broad, and depressed ; twenty-one to twenty-four 

 teeth on each side above and below, which are conical, and often worn down : some individuals are more than 

 fifteen feet in length. It appears that they are found in the Mediterranean as well as in the Ocean [and, though 

 seldom taken, on account of the extreme rapidity of their movements, they are not rare in the British seas. There 

 are numerous others]. 



M. de Blainville separates from these first Dolphins, under the term 



Delphinorynchus, — 

 Those species in which the snout, though elongated and slender, is not separated from the forehead 

 hy a distinct groove. 



* Except in the genus Inia, d'Orbigny, wherein there are true 

 nustaehes — Ed. 

 ' This animal must not be confounded with a fish Coryp *ixna 



Hippuris), celebrated for its beautiful iridescent colours, which bears 

 the same popular name — Ed. 



