BY J, DOUGLAS OGILBY. 63 



provided with a pair of small cusps on either side of the base; the 

 outer row consists of eight teeth (on each side of the second 

 median tooth) which decrease in size from the front, and have 

 each a prominent cusp directed moi'e or less obliquely backwards 

 and one or more subsidiary cusps, the second and third having a 

 single strong acute cusp at the base posteriorly, the fourth one 

 anteriorly and two posteriorly, the others three or four on either 

 side; the fourth, fifth, and sixth are about equally broad at the 

 base and conspicuously broader than the others;* between the 

 last serrated tooth and the angle of the mouth are ten series of 

 small chisel-shaped teeth, each series consisting of seven teeth, 

 those in front being the largest. 



Lower j a w. — Median tooth with a strong mesial cusp which 

 is inclined towards the right and four lateral cusps on each side, 

 the distal pair being the strongest; behind these are three similar 

 teeth; the outer row of cutting teeth is inserted on a line with 

 the anterior tooth of the median series; each tooth is provided 

 with sixf functional cusps which decrease in size from the front 

 in regular gradation, the anterior and principal cusp having from 

 five to seven serrte on its basal edge in front; these serrte increase 

 in size outwards; the third and fourth teeth are the largest, and 

 there are four series behind the outer row; as in the upper jaw, 

 there are ten series of chisel-shaped teeth beyond the last cutting 

 tooth. 



Dimension s. — The distance between the base of the median 

 tooth of the upper jaw and the end of the dentigei'ous portion of 

 the palato-quadrate is three-fourths of its distance from the angle 

 of the mouth, which is a little less than that between the last 

 teeth of each ramus and five-sixths of that between the angles of 

 the mouth; the distance between the middle of the base of the 

 lower median tooth and the end of the last cutting tooth is two- 

 thirds of the space between the two posterior cutting teeth. 



* Owing to the state of the jaws, I am unable to say how many series 

 of teeth are present. 



t Sometimes a minute seventh cusp is present. 



