380 CRETACEOUS REPTILES. 
hitherto obtained was here found; and it was for a long time the boast of the 
town of Maéstricht, until the capture of that place by the French, when it was 
removed to Paris, where it has since remained. A fine cast of this unique speci- 
men may be seen in the Royal College of Surgeons in London. The teeth resem- 
ble in their form those of the Monitor lizard; but the presence of teeth on the 
bones of the palate, called ‘ pterygoids,’ is a character by which the Mosasaurus 
more resembled the Iguana. The vertebrae have a convexity at one end and a 
concavity at the other, and are reckoned at upwards of 130 in number: the tail 
was very long, deep, and flattened from side to side, so as to form a powerful 
organ for swimming. From which characters, together with the number, size 
and shape of the teeth, it is plain that the Mosasauwrus was an aquatic carnivorous 
reptile, most probably marine, and a formidable enemy to the fishes of the 
ancient ocean in which the deposits of the chalk were formed. 
Mosasaurus gracilis, Owen (Tab. XXXVIL. figs. 1-5 ; Tab. XX XIX. figs. 7, 8, 9). 
Cuvier* says of the great Mosasaurus of Maéstricht, which is entered in the 
catalogues of M. v. Meyer and M. Pictet under the synonyms M. Camperi and 
M. Hofmanni, that ‘all the teeth are pyramidal, a little curved, with their ex- 
ternal surface flat (‘plane’) and divided by two sharp ridges from the internal 
surface, which is round or rather semi-conical.” Messrs. Von Meyer} and 
Pictet | repeat Cuvier’s description of the external characters of the crowns of 
the teeth ; the one says, “‘ ihre Aussenseite ist eben ’—their outer side is flat or 
level ; the other, ‘‘ leur face externe est plane.”’ My description§, that ‘‘ their 
outer side is nearly plane, or slightly convex,” was founded on an examination 
Fig. 1. of the magnificent fossil skull in the Parisian Museum, the 
original of Cuvier’s description ;—and the contour of the 
ie base of the crown of a maxillary tooth of the Mosasaurus 
Hofmanni given in fig. 1, is taken by accurate admeasure- 
ment from a perfect specimen from the Maéstricht chalk : 
the enameled crown of this tooth was 2 inches (5 centime- 
Section of'touth: ters) in length ; the rest of the tooth was formed by the en- 
Mosasaurus Hofmanni. — Jarged coarse osseous fang ; the total length of the tooth 
being 4 inches 10 lines (123 centimeters). Dr. A. Goldfuss, in his highly in- 
teresting and instructive account|) of the skull and teeth of the Mosasaurus 
Maéstricht, 
* Ossemens Fossiles, 4to, v. pt. 2. p. 322. + Paleologica, p. 219. 
{ Traité élémentaire de Paléontologie, ii. p. 63. § Odontography, 4to, p. 258. 
| Nova Acta Acad. Nat. Cur. t. xxi. pt. 1. p. 175. 
