60 MOSASAURUS. 
‘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 successional tooth like that of the preceding specimen. 
Attached to the same specimen, but not represented im 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 
No. 14. 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 of the extra-alveolar portion of 
the fang communicates with the pulp cavity its entire 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 surfaces 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 antero-internally for the 
accommodation of a successional tooth, as represented in 
Fig. 5, e. The excavation communicates with the pulp 
cavity on a level with the bottom of the extra-alveolar por- 
tion of the fang, as seen at f 
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 f. 
No. 15. 
