76 Mr. Owen on the Zeuglodon Cetoides. 



The idea, indeed, that the Zeuglodon was a reptile was not suggested by an 

 examination of the teeth, but of the vertebrae, of which the most entire speci- 

 men is now on the table, being the original from which Dr. Harlan's figure is 

 taken, and respecting which M. Dum^ril* has already expressed his opinion, 

 that it presents the characters rather of a cetaceous than a saurian animal (PI. 

 VIII. fig. 6). 



This vertebra most resembles, in fact, the anterior caudal vertebrae of the Hy- 

 peroodon. The most characteristic proof of its cetaceous nature is afforded by the 

 traces of the original separation and subsequent union of the epiphyseal laminar 

 pieces constituting the anterior and posterior articulating surfaces of the body, 

 while the actual union of these plates indicates a tendency to a higher mammi- 

 ferous character ; the same epiphyses, for example, become anchylosed to the 

 bodies of the vertebrae in the herbivorous Cetacea as in the mammiferous qua- 

 drupeds. 



In the bodies of the smaller vertebrae of the Zeuglodon, however, the articular 

 epiphyses are wanting ; and Dr. Harlan himself infers, from the common occur- 

 rence of this condition, that there were originally three separate points of ossifi- 

 cation in the body of the vertebraf. It is the persistence of this structure, which 

 does not exist in any Saurian, that forms the most prominent character of the ver- 

 tebrae of the Cetacea. It is to the presence of the two depressions or perforations 

 in the lower part of the body of the vertebrae, and to the supposition that this 

 structure peculiarly characterized the Plesiosaurus, that the belief of the saurian 

 character of the Zeuglodon is mainly attributable ; but the fact that this structure 

 is present in the vertebrae of many Mammalia, and especially of the Whales, en- 

 tirely invalidates the inference. 



The vertebrae of most Sauria exhibit the articular depressions for the superior 

 arch, which, from the want of more intimate union with the body, is generally lost 

 in fossil vertebrae ; but in the large vertebra of the Basilosaur we have clear proof 



" After the occurrence of a long spell of rainy weather, a part of the hill slid down near to the waters 

 edge, and thereby exposed twenty-eight of these bones, which had been until then covered by an in- 

 cumbent mass of earth about forty feet thick. When these bones were first seen they extended in a line, 

 which, from what the person living near the place showed nie, comprised a curve, measuring upwards of 

 400 feet in length, with intervals which were vacant. The person referred to destroyed many of the 

 bones by employing them instead of andirons in his fire-place, and I saved what remained from the sa)ne 

 fate. I think, however, that a great many more bones belonging to the same animal are yet covered, and 

 will gradually appear as the soil and marl shall be washed off by the rain." — Extract from a letter from 

 Mr. H. Bree in Dr. Harlan s Medical and Physical Researches, 8°, 1 835, p. 337- 



* Compte Rendu des Seances de I'Academie des Sciences, Oct. 22, 1838. Dr. Buckland gave a similar 

 opinion on the vertebrae of the Basilosaurus on the occasion of the discussion of the affinities of the 

 Thylacoiherium, November 21, 1838. 



t Loc. cit. p. 356. 



