58 



M O S A S A T^ R U S . 



no trace of a cavity for a successor, and the entrance to its pulp cavity is like that 

 in the preceding specimen. 



10. A mutilated tooth, from Burlington C!ounty, New Jersey, presented to the 

 Academy of Natural Sciences by Charles C. Abbott. It is intermediate in form 

 and size with the specimens numbered 7 and 8. The outer surface of the crown, 

 corresponding with the antero-posterior diameter, is eight lines and a half, and it 

 exhibits three planes. The inner surface exhibits eight planes, and the transverse 

 diameter equals the former one. The accompanying outline, No. 8, represents a 

 section near the base of the crown. The fang is curved cylindroid, slightly com- 

 pressed, and measures two inches and a quarter in length. Its inner side posteriorly 

 exhibits a small lenticular excavation, three lines long, produced by a successional 

 tooth. 



1 1 . Two teeth, which have lost their fangs, from IMonmouth County, New Jersey, 

 presented to the Academy of Natural Sciences by E. D. Cope. The specimens, 

 represented in Fig. 5, Plate X, and Fig. 12, Plate XI, look as if they had been 

 derived from the same individual. They correspond in form with the more familiar 



one viewed as characteristic of Mosasaurus, but they are smooth or 

 devoid of subdivisional planes, or at most exhibit only the feeblest 

 disposition to their development at the base of the crown. The 

 pulp cavity, within the specimens, presents the outward form of 

 the croAvn. The length of the more perfect specimen. Fig. 5, from 

 the enamel border of the base of the crown to the worn apex, is 

 twenty-two lines ; its antero-posterior diameter at base is eleven 

 lines ; its transverse diameter the same. The accompanying outlines. No. 9, repre- 

 sent transverse sections near the base of the cro\vn, and just below and above the 

 middle. The length of the crown of the other specimen. Fig. 12, is two inches. 



12. An entire tooth, from Monmouth County, New Jersey, presented to the 

 Academy of Natural Sciences by Dr. J. H. Slack. It is represented in Fig. 4, Plate 



IX, and is intermediate in size with those of the approximate Figs. 

 ^°' ■ 2 and 3, to which it also bears a general resemblance in form. 



The unworn croAvn is twenty lines long, and is nearly circular in 

 transverse section, as represented in the accompanying outlines, 

 No. 10, taken from the base and below the middle. The diameter 

 of the base of the crown antero-posteriorly is ten lines and a half; 

 the transverse diameter nine lines and a half. The ridges separating 

 the surfaces of the crown are minutely denticulated, and both surfaces are smooth 

 or entirely devoid of subdivisional planes and striations. The inner surface is a 

 little more extensive than the outer one, as represented in the accompanying 

 sections. 



The fang is straight, cylindroid, and measures two inclies and a half in length 

 and thirteen lines in diameter. It exhibits no evidence of having been coossified 

 with its alveolus, and on the inner side posteriorly, as represented in Fig. 4, h, it 

 presents a small excavation for tlie accommodation of a successional tooth. At the 

 free extremity it presents a funnel-shaped pit, prolonged into the central canal of 

 communication with the pulp cavity. 



