Microchcerus erinaceus {Wood). 41 



be made out : it is semi-procumbent, with the crown set well 

 forward on its single root. 



The first premolar of the series (pm 2) is smaller than the 

 canine, single-rooted, and with a small talon. Premolars 3 

 and 4 are twc-rooted, square in outline, and with a large 

 external and small internal cusp; they are not in any way 

 molariform in pattern. The first two molars are square in 

 shape and subeqnal in size, being 3*75 mm. in length and 

 4 mm. across. The protocone, paracone, and metacone are 

 conical, roughly equal in size, and in the unworn tooth 

 moderately sharp. The hypocone is somewhat smaller and 

 is placed behind the protocone, but a little more in towards 

 the median line of the palate. The protoconule arises near 

 the anterior cingulum a little in advance of a line connecting 

 the protocone and paracone ; the hypoconule occupies a similar 

 position in respect to the metacone and hypocone and in the 

 first molar equals the protoconule in size, in the second 

 molar it is smaller, and in the third i3 hardly developed at 

 all. A strongly marked cingulum runs along the front and 

 outer borders of these teeth ; there is, moreover, a tendency 

 to small secondary wrinklings in the enamel on the surface. 



The last molar is smaller, rounder, and generally less 

 developed than the rest. A small but exceedingly clearly 

 marked mesostylar tubercle is present on all three teeth near 

 but separated from the cingulum between the para- and 

 metacone. 



The mandible has the following measurements : — 



cm. 



Complete length between perpendiculars 4*35 



Height of articular surface from base of angle .... 3 do 

 (Greatest depth of ramus (between pm 1 and ml) .... "85 

 Depth of ramus under in 3 -75 



The articular surface is high up and is at the same level as 

 the coronoid process. The angle is strongly marked and 

 projects downward. The ramus is stout and turns up rather 

 abruptly in front of the large first tooth to form a "chin." 



There are eight teeth in the lower dentition. The front 

 one is broken away in all specimens, but the deep alveolus, 

 2 mm. in breadth, shows that it must have been of fair size. 

 Wood, in his figure of the type specimen before it became 

 damaged, shows it as a long semi-procumbent tooth. Imme- 

 diately behind this, lying to the outside of the series, is a 

 small socket which represents either the third incisor or the 

 canine. The following six teeth lie in a closed curved series 

 and consist of three premolars and three molars. The first 



