CONTENT SOFA BONE CAVE. 5 



convex in the antero-posterior direction. There are some unattached hooked pro- 

 cesses, which I suspect to be angles of the mandible. 



The dental formula is i. J-; c. - ; m. |. The incisors have a moderately thick 

 enamel layer, which is wrapped round the external angle a short distance. 

 Their sculpture is not deeply cut. The molars are composed of Vertical columns 

 of dentine inclosed in and separated by a sheath of enamel. The columns are 

 more or less transverse, and are neither confluent nor divided in any of the teeth. 

 They number four in the superior teeth, excepting in the last molar where there 

 are five. The entire tooth is inclosed in a thin layer of cement. The superior 

 molars are curved bow-shaped, the convexity being directed forwards at the middle 

 of their length. The enamel plates are then directed backwards on the grinding 

 faces. The extremities of the roots are simple and contracted to an obtuse termi- 

 nation. The inferior molars differ in their form, being straight and directed ob- 

 liquely forwards in the jaw. From this it results that their triturating surfaces 

 are oblique to the axis of the teeth, while those of the superior molars are trans- 

 verse to the axis of the middle portion of the shaft. There are but three columns 

 in all of the inferior molars. 



Vertebra;. The atlas has widely expanded transverse processes whose base is 

 about equally divided behind by the vertebral foramen. The vertebral canal soon 

 issues on the inferior face, and again entering the transverse process near its middle, 

 divides and issues in two foramina. One of these is on the superior aspect of 

 the base of the transverse process, and the one opposite to it on the side of the 

 neural canal. There is no hypapophysis nor tuberculum atlantis. The facets for 

 the axis are directed obliquely inwards. 



The axis is rather short and the neural spine long and directed upwards. Its 

 section is triangular ; the odontoid process is short and stout, with subcylindric 

 section. Opposite articular extremity flat. 



The lumbar centra are about as wide as long, and with nearly flat articular faces. 

 The sacral vertebra?, although adherent in several individuals, preserve the suture 

 in all of them. They are more elongate than the lumbars, and contract rapidly 

 in diameter ; the difference between the anterior and posterior dimensions of the 

 first being considerable. The centra of all behind the first are much depressed, 

 and the intervertebral foramina are large. The sacral diapophyses are greatly 

 expanded, especially anteriorly ; their iliac suture is a plane sloping inwards and 

 upwards. The only caudal vertebra preserved is short and wide, has stout diapo- 

 physes, and no facets for chevron bones. As there is no trace of neurapophyses on 

 this centrum, I infer that the tail is short. 



Anterior Limb, The scapula is represented by portions of those of several indi- 

 viduals. In these, the spine is well developed, rising rather abruptly from near 

 the neck. The coracoid process is a short, stout hook. I have not found a clavicle 

 among the bones. 



The fore-limb is of smaller proportions than the posterior one. The greater 

 tuberosity of the humerus is crest-like, extending along one side of the head, but 

 not rising much above it. The lesser tuberosity is subround and very protuberant, 

 inclosing a deep and wide bicipital groove, with the extremity of the greater 



