GO 



MOSASAURUS. 



No. 14. 



The accompanying outline, No. 13, represents a transverse section taken from near 

 the base of the crown. The fang is three inches and three-quarters in length, and 

 exhibits a cavity for a successioual tooth like that of the preceding specimen. 



Attached to the same specimen, but not represented in the figure, there is a 

 coossified fragment of the fang of the tooth, which was situated in advance, and 

 which was about one-half excavated to accommodate a successional tooth. 



A third specimen, much mutilated, nearly resembles the former one. The inner 

 and outer surfaces of the crown are nearly equal in extent, and each is subdivided 

 into seven planes. The antero-posterior diameter at the base 

 is fourteen lines and three-quarters; the transverse diameter 

 thirteen lines. The outer of the accompanying outlines. No. 

 14, represents a section at the base of the crown. 



The fang is half excavated away at the inner side and bot- 

 tom for the accommodation of a successional tooth. The ex- 

 cavation just below the level oi the extra-alveolar portion of 

 the fang communicates with the pulp cavity its entu-e breadth. 

 A fourth specimen, much mutilated, bears a near resem- 

 blance with the former two, but is considerably smaller. The crown, from its worn 

 apex to the base, is sixteen lines long ; its antero-posterior diameter at base is 

 twelve lines and a half; the transverse diameter ten lines. The inner and outer 

 surfaces are nearly equal in extent, but the latter is even slightly the greater, and 

 is divided into seven planes, while the former is divided into six. The inner of 

 the accompanying outlines, No. 14, represents a section of the crown near the base, 

 — appearing more elliptical than in preceding sections. 



The fang is about two inches and three-quarters long, and is nearly half exca- 

 vated for a successor. The excavation communicates with the open canal of the 

 pulp cavity. 



The fifth specimen, represented in Fig. 5, Plate IX, consists of a tooth, together 

 with the fang of a second, coossified with an alveolar fragment of the jaw. 



The crown of the tooth has its apex broken and its posterior ridge worn. 

 When perfect it appears to have been about two inches long; and its elliptical 

 section at base measures fifteen lines antero-posteriorly and thirteen transversely. 

 The inner and outer svirfaces are nearly equal, the former being subdivided into six, 

 the latter into eight unequal planes. The accompanying out- 

 lines. No. 15, represent sections near the base and middle of 

 the crown. 



The fang of the tooth is three inches and three-quarters 

 long, and is one-half excavated antcro-internally for the 

 accommodation of a successional tooth, as represented in 

 Fig. 5, e. The excavation communicates Avith the pulp 

 cavity on a level with the bottom of the extra-alveolar por- 

 tion of the fang, as seen at/. 



The fang of the other tooth is about one-third excavated postero-internally, as 

 represented on the right of Fig. 5, e, and the excavation has exposed the pulp 

 cavity of the tooth as seen at/. 



