214 On the Dinotherium Grgantenm. 



nions of Buckland or Kaup, but proposes one of the same ge- 

 neral nature with that of Blainville. He writes in the folloAving 

 terms to the French Academy of Sciences, 



" That he has at length formed an opinion concerning this animal which 

 very nearly approaches to that delivered by IM. de Blainville, but that he has 

 been led to this conclusion by considerations which are altogether of a diffei'- 

 ent character. It is not, he remarks, by investigating among the different 

 animals, which are those whose heads most nearly approach to that of the 

 Dinotherium, that I have been led to arrange this last among the Cete ; but, on 

 the other hand, by seeking to discover in the ci anium the characters which it 

 indicates ; the arrangement which the other parts of the body must have assum- 

 ed in regard to it, and the mode of life which this organization would necessarily 

 require. In attributing to the Dinotherium a mode of life wholly aquatic, 

 continues the author of the letter, I ground my opinion principally upon the 

 shape and position of the occipital condyles, a position which proves that the 

 series of the cervical vertebrae, and consequently that of the dorsal also, were 

 in a horizontal direction ; a position which could not occur in any of the ter- 

 restrial mammalia. In fact, according to a law which I shall have occasion 

 to establish in a work upon the anatomy of the cat, which I hope will speedily 

 be published, we ai-e led to admit that in all the teriestrial mammalia the 

 occipital condyles must be directed downwards for bipeds, and obliquely 

 downwards and backwards for quadrupeds, so that the series of the cervical 

 vertebrae, which is articulated with the condyles, may have the same direc- 

 tion, and so may contribute to support the head, and to arch it upwards and 

 forwards, in its continuance with the series of the dorsal vertebrae. Now, 

 in the Dinotherium, putting the plane of the molar teeth horizontal, the oc 

 cipital condyles are directed obliquely backwards and upwards, a position 

 which is altogether incompatible with a terrestrial mode of life, but perfectly 

 possible in an aquatic animal, in which every part of the body, the head 

 among the rest, is directly supported by the water. Also, for this condition, 

 it is likewise necessary tjiat the cervical vertebrae should be directed back- 

 wards, as in truth we find them to be in the whales and in fishes. This first 

 and principal character is, in addition, supported by the flattening of the occi- 

 pital at its upper and back part, so furnishing the plan of the attachment of 

 the extensive muscles of the head. This flattening has already been pointed 

 out as a character which the Dinotherium possesses in common with whales, 

 but not as indicating in itself an aquatic life. In fact the extensor muscles, 

 by being fixed to this flattened portion of the head, would lose a great part of 

 their power if the neck were directed downwards, the arm of the lever by 

 which they act being thereby very much shortened. Thus, it is not because 

 the Dinotherium exhibits in common with whales a flattening of the upper 

 and back part of the ■ ranium, that I judge that we must consider it a cetace. 

 ous animal, but because an aquatic life is a condition of this flattening in 

 both the one and the other. 



The disposition of the occipital condyles also proves that the Dinotherium 

 was, not one of the amphibiae, like the hippopotamus, the seals, and even the 

 manatee, but an animal which, like the ordinary cetacea, can never come out 

 of the water, except we at the same time admit very extraordinary condi- 



