144 SKETCH OF THE HISTORY OF MAMMALIA. 



table delicacies from ourselves ; for few, we believe, 

 would now relish the rank, oily, fishy flesh of this ani- 

 mal. Length about five feet. Fig. 94* represents the 

 skeleton. 



Fig. 91 represents the skull of the dolphin {Delphinus 

 Delphis), a species, celebrated by the ancients, and 

 resembling the porpoise in its habits and food. The 

 aquatic evolutions of these animals, as seen sporting 

 around ships, apparently for the sake of amusement, their 

 varied and rapid turns, and gambols, are well described 

 by Ovid — 



" Undique dant saltus, multaque adspergine rorant ; 

 Emerguntque iterum, redeuntque sub aequora rursus, 

 Inque chori ludunt speciem, lascivaque jactact 

 Corpora, et acceptum patulis mare naribus efflant." 



The Narwhal (^Monodon monoceros). 



The genus Monodon, of which the narwhal is the 

 only recognised species, is provisionally placed by Cuvier 

 in the family Dclphinidae. It evidently forms the type 

 of a distinct group. Among the Cetacea inhabiting the 

 dreary realms of the Polar Ocean, the narwhal, if not 

 the largest or among the largest, is nevertheless one of the 

 most remarkable : its general form resembles that of the 

 porpoises ; it has, however, no teeth, properly so called, 

 but two ivory tusks, or spears, implanted in the inter- 

 maxillary bone, but of which the right remains usually 

 rudimentary and concealed during life. The left tusk, 

 on the contrary, attains to the length of from five to 

 seven or eight and sometimes ten feet in length, and 

 projects from the snout in a right line with the body, 

 tapering gradually to a point, with a spiral twist (ropelike) 

 throughout its whole extent (Fig. 95, where, by an over- 

 sight, the tusks have been transposed). In its structure 

 and growth this tusk resembles that of the elephant, 

 being hollow at its base or root, and solid at its extremity. 

 It is in the male only that this spear-like weapon, under 

 ordinary circumstances, becomes duly developed, the 

 lemales (and indeed the young males) having the left as 



