66 



These are all held together by the natural matrix in which the 

 whole was originally imbedded. Near the union of the upper 

 jaw with the cranium, are some sutures, but not sufficiently ex- 

 posed to enable one to identify them. At the tip of the jaw, 

 there is a fragment of bone without teeth or alveoli, and differing 

 in the appearance of its texture from the bones adjoining; this is, 

 probably, a fragment which has found its way to its present lo- 

 cality by accident, and is retained there by the matrix. The 

 lower jaw corresponds with the upper in its elongated form, but 

 the condyles and processes are wanting. 



The teeth, organs of great innportance in determining the 

 natural affinities of any animal, are many of them in a complete 

 state of preservation, and some so completely exposed as to be 

 studied with great ease. Through Dr. Koch's kindness. Prof. W. 

 was enabled to give them a satisfactory examination. The 

 crowns are laterally compressed, of a somewhat triangular form, 

 but deeply indented on the edges, and all which were sufficiently 

 exposed for examination, were implanted into the douhle alveoli 

 of the jaw ly means of douhle roots. Here is the most positive 

 evidence that the individual to which they belonged was no 

 reptile, but a warm-blooded, mammiferous animal ; for, according 

 to the odontological rule, no animal not mammiferous ever pos- 

 sesses a tooth with double roots, implanted into double alveoli or 

 sockets. The teeth of sharks are no exception, for, although 

 there exists in them an approximation to a double root, they are 

 attached to the jaw by ligament only. 



II. Vertebral column. This consists of a series of bones which 

 could never have belonged to the same individual, as is obvious 

 from the fact that they manifest different degrees of ossification, 

 and must, therefore, have belonged to individuals of different 

 ages. The plates attached to the extremities cf the bodies of the 

 vertebree are, in some instances, perfecdy coossified, in others 

 not, or, in some cases, detached, leaving the imperfectly ossified 

 surface exposed. In some of the vertebral bones the spinal canal 

 is represented by a cast of its cavity, which, as already stated, 

 would nearly equal the diameter of that of the supposed cranium, 

 which it could never do in a warm-blooded animal, especially a 

 cetacean, where the brain acquires a high degree of development. 

 The bodies of the vertebrae and the ai'ticulating processes, do not 



