SKULL AND OTHER BONES OF LOXOMMA ALLMANNI. 211 



foramen is the upper edge of the cotyloid cavity of the basiocci- 

 pital. Owing to the compression of the skull, the foramen, how- 

 ever, is not easily made out. 



External to the facets there is on each side a rather pointed 

 process, apparently for muscular attachment ; and beyond these 

 again, at a short distance, are the tooth-like processes of the 

 underside of the mastoids, mentioned in the description of the 

 upper surface of the skull. 



Below these parts is the inferior surface of the skull, described 

 in Section II. 



IV. The Mandible (Plate III., figs. 2, 3).— Two half-mandi- 

 bles, right and left, occurred, as is stated at the commencement 

 of this description, two or three feet apart and not far from the 

 skull ; they are of the proper size to fit it, and most probably 

 belonged to it. 



The right half (fig. 2, half the natural size) is almost perfect ; 

 its alveolar border is quite so, it exhibits the teeth in a beautiful 

 state of preservation ; and its exterior is covered with the pecu- 

 liar reticular sculpture. It measures nearly fourteen inches and 

 a half in length, and at the widest part, which is about four 

 inches from the posterior end, two inches and three-quarters in 

 width ; from this point it tapers gradually to the anterior end, 

 where it is perfect, and little more than an inch in width. 



A narrow groove can be observed to run nearly the whole way 

 along the inferior border of the specimen, beginning below the 

 articular projection; whether this is a mucus - groove, or what 

 its signification is, is not easily determined. 



The inferior margin is slightly convex ; the upper or alveolar 

 somewhat concave, with a slight eminence in front supporting 

 the first large tooth. The anterior end terminates in a symphy- 

 sis which is rather deep, and, as seen in another specimen, ex- 

 tended downwards and backwards, its depth being one inch and 

 three-quarters, its breadth at top five-eighths of an inch, below 

 which, it lessens to one quarter of an inch. 



Near the posterior end the outer layer of the bone in our 

 specimen is for a short space altogether wanting; but beyond 

 this the articular end is well preserved, at least at the outer 



o 



