MOSASAURUS. 69 



the other from near Woodbury, Gloucester County, New Jersey, presented to the 

 Academy by Dr. J. L. Burtt. The former is represented in Fig. 12, Plate X; the 

 latter in Fig. 13, of the same Plate. 



They resemble the crown of the tooth last described, but are in a No. 27. 



better condition of preservation. They are divided in the usual 

 manner into two surfaces, of which the inner is rather more convex 

 than the outer, and both are distinctly subdivided into planes. The 

 New Jersey specimen, of which the outline, No. 27, represents a 

 transverse section, presents four planes on its outer side and seven 

 on its inner side ; and it measures eighteen lines in length, nine lines 

 and three-quarters antero-posteriorly at base, and seven lines trans- 

 versely. The Delaware specimen, of which the outline. No. 28, is a 

 section, exhibits seven planes externally and internally, and measures seventeen lines 

 long, nine lines and a quarter antero-posteriorly at base, and six lines and a half 

 transversely. 



28. A tooth, from Mount Holly, Burlington Coimty, New Jersey, presented to 

 the Academy of Natural Sciences by Dr. S. G. Morton. The crown has its apex 

 broken off, and the ridges dividing the former are considerably worn. When 

 perfect it has been about an inch and a half long, with the base ten lines and a 

 half antero-posteriorly, and eight lines transversely. The surfaces are devoid of 

 subdivisional planes, or exhibit only the faintest traces of several towards the back 

 border of the crown. The inner surface more convex than the outer, has the curve 

 of its base eighteen lines in width, while the outer one is thirteen in width. 



The fang is entire, and appears not to have been coossified with its alveolus. 

 The exserted portion forms a curved shoulder measuring externally only five lines 

 in length, while at the border it is sixteen lines in antero-posterior diameter, and 

 thirteen lines in transverse diameter. The intra-alveolar portion of the fang is an 

 inch and a half long, straight, somewhat compressed, and tapering below. On its 

 inner side posteriorly is a small excavation for a successional tooth. 



29. A fragment of a jaw, with portions of three alveoli, of which one contains 

 the fang of a tooth deeply excavated and containing a successor. The specimen 

 is from Marlboro, Monmouth County, New Jersey, and was loaned to me, from the 

 collection of E.utger's College, by Prof. Cook. 



The successional tooth, of which an inner view is represented No. 29. 



in Fig. 11, Plate XI, is a crown with a large interior pulp cavity 

 and thin walls. From the apex to the broken edge of the base 

 it measures about twenty-two lines in length. In transverse 

 section it is irregularly elliptical, as represented in the outlines, 

 No. 29 ; its inner curvature being more convex and longer than 

 the outer. The anterior and posterior acute ridges are minutely denticulated, and 

 the surfaces they separate are totally devoid of subdivisional planes. 



30. Two small teeth, from Freehold, Monmouth County, New Jersey, belonging 

 to the collection of Dr. C. Thompson, and loaned to me through Prof Cook. They 

 are represented in Figs. 14, 15, Plate X, and appear to have belonged to the same 

 individual. 



