SKELETON OF CETACEA. 415 



tree, — and the rest of the bony organisation becomes intelligible. 

 That of the hind-foot has been explained : the concomitant extent 

 of muscular origin afforded by the broad scapular plate with its 

 many ridges, crests, and processes, is thereby accounted for. The 

 necessity of the firmness imparted to the shoulder joints by the 

 perfect clavicles abutting at one end against a large ^ manubrium,' 

 at the other end against the conjoined acromion and coracoid, be- 

 comes obvious. The fore-foot retained three huge claws to effect 

 an adequate grasp of the trunk or bough : for their due and varied 

 application the fore-arm enjoys all the variety and freedom of 

 movements which an arm terminated by a hand possesses. A 

 tree being prostrated and its foliage thus brought within reach, 

 every indication in the skull of the size, strength, flexibility, and 

 prehensile power of the tongue harmonises with the foreo-oino- 

 teleological conclusions. The Megatherioids, like the Giraffe, 

 thus plucked off the foliage on which they fed. In the rido-ed 

 crowns of the grinders of the Giant Ground-Sloth we discern 

 the power of crushing coarser parts — a greater proportion of 

 twigs and stems, e.g. — of the foliage than the diminutive Tree- 

 Sloths take. It needed only evidence of the occasional occurrence 

 of what might happen to a beast in the fall of a tree which it had 

 uprooted, to seal the foregoing physiological inferences with the 

 stamp of truth : and the skeleton of the Mylodon in the Hun- 

 terian Museum^ shows that evidence above the right orbit, and 

 at the back part of the cranium, marked/*, fig. 267. 



§ 184. Skeleton of Cetacea. — This is characterised by the 

 coarseness and greasiness of the osseous texture, by the shortness 

 of the cervical and the length of the caudal regions, by the loose 

 and diminutive pelvic bones, by the absence of pelvic limbs, and 

 by the large size of the skull, due in most to that of the jaws, 

 which in some Whales {^BalcenidcB, fig. 159, Physeter macroce- 

 phalus) is excessive. 



A. Vertebral Column. — Althouo-h there is as little outward sis^n 

 of a neck in a whale as in a fish, the same number of cervical 

 vertebrae are present as in the giraffe. The atlas, fig. 283, i, is the 

 largest, is characterised by its huge and ai)proximate articular cups, 

 c, for the occipital condyles, and by the substitution of a hypapo- 

 physis for the true centrum, which coalesces as an odontoid process 

 with that of the axis : both these vertebra? are antero-posteriorly 

 compressed and transversely extended, and the five succeeding 

 cervicals are still shorter in proportion to their height and breadth : 

 they are, in fact, lamelliform, without reciprocal movement, and 

 usually exhibit a greater or less extent of confluence, the whole 



' XCII-. p. 63, no. 377. 



