4 MEMOIR ON MOSASAURUS 



Dr. S. G. Morton, in his Synopsis of Organic Remains, mentioned " teeth and 

 vertebrae found in Monmouth, Burlington, and Gloucester counties, in New Jersey, 

 and at St. George's, in Delaware " ; and in the Proceedings of the Academy of 

 Natural Sciences, in November, 1844, described some specimens from New Jersey, 

 and, finding some differences between them and the Mosasaurus of Maestricht, 

 proposed provisionally for the former the name of M. occidentalis. 



The next notice of Mosasaurus is the very full and valuable paper of Goldfuss, 

 published in 1844, " On the Formation of the Cranium of Mosasaurus, with a 

 Description of a New Species," which he calls 3£. Maximiliani.* 



Among the donations to the Academy of Natural Sciences of Philadelphia in 

 September, 1848, was a portion of a jaw of Mosasaurus, with two nearly perfect 

 teeth, from Freehold, New Jersey ; and since this paper was read, another large 

 fragment has been also presented from a neighbouring locality. 



I have had in my cabinet for several years vertebrae from Alabama answering 

 precisely to the description and figures of those of Mosasaurus, and agreeing, except 

 in size, with the vertebrae from New Jersey in the museum of the Academy. I have 

 always considered them as belonging to a small species of Mosasaurus. Lately, 

 I received from Alabama a portion of a tooth, which must have belonged to a 

 small species. 



I have large vertebrae from the Eocene marl of Mr. J. A. Eamsays, Ashley River, 

 near Charleston, which resembled those figured and described by Faujas St. Fond.f 



In the American Journal of Science, % Mr. F. S. Holmes mentions vertebrae from 

 the marl of Ashley River which are similar. During the last year Chancellor 

 Dargan, of Darlington, South Carolina, was kind enough to send me some frag- 

 ments of bones, chiefly cetacean, found in the Pliocene marl of his neighbourhood, 

 among which I found a portion of a lower jaw of Mosasaurus, with the alveolar 

 part of a tooth. 



I am indebted to Dr. Willkings, of Wilmington, North Carolina, for a vertebra, 

 identical with those from New Jersey and Ashley River, found in the Eocene of 

 his locality. These references comprise our present knowledge of Mosasaurus. 



In the Maestricht individual (which has been called Mosasaurus Camperi and M. 

 Hoffmanni, but is usually designated by the latter name), the teeth are described as 

 solid and having no true roots, but supported on expanded conical bases anchylosed 

 to the summit of the alveolar ridge of the jaws. These arise from the ossification 

 of the pulpy matter which had secreted the teeth, and are united with and form 

 part of the maxillary bone, the secondary teeth being formed in the substance 

 of this body or ossified pulp. A shallow socket is left where the tooth and its 

 supporting base are shed. They are still further attached to the jaw by the ossifi- 

 cation of the capsule that furnished the enamel.§ 



" The form of the teeth is likewise different from that hitherto observed in any 



* Nov. Act. Acad., Vol XIII. " Der Schadelbau des Mosasaurus," etc. 



t Hist. Nat. de la Montagne de St. Pierre, Tab. VIII. et IX. 



I Vol. VII., 1848. § Cuvier and Owen. 



