EXTINCT LEMUROIDS 697 



erinaceus, of the upper Eocene of Hampshire, of which the corre- 

 sponding teeth are shown in B of the same figure. In this genus, 

 according to Dr. Schlosser, the dental formula is i f- , c |, p f, m $-, 

 or the same as in the existing Tarsim ; but it is not improbable that 

 in some instances the first lower premolar may have been developed. 

 The upper molars of M. erinaceus differ from those of M. antiquus 

 by the simpler structure of their columns and the smaller size of 

 the external cingulum, which lacks the median cusp found in the 

 latter. The angle of the mandible is produced into a large hook- 

 like flange Avhich at once 

 distinguishes the genus 

 from all existing Lemurs ; 

 and the anterior lower 

 premolar is not canine- 

 like. M. antiquus is of 

 very small size, but the 



larger M. nltmriJtti of the (C^^Fl^^n^Slv $ '' 

 same deposits conies 



nearer in dimensions to FIG. 332.-The last nve right u P1 ^r cheek-teeth of 3/tcro- 

 ... . _ chcerus anlvptus (A) &nd Mtcrochcerus ennaceus(B). Twice 



M. enmceUS. Ihe Upper na t ura i size, and natural size. 



molars decrease in size 



from the first to the third, the first and second having a median 

 cusp in the external cingulum, by which they are readily dis- 

 tinguished from the corresponding teeth of the under-mentioned 

 genus Hyopsodus. The third upper molar differs from that of 

 Hyopsodus by its small size and the abortion of its posterior columns. 

 The skull approximates to that of the living genus Galago, exhibit- 

 ing the same inflation of the auditory bulla. The upper molars 

 are also not unlike one species of that genus, but the fourth upper 

 premolar has but one outer cusp, as in Chirogaleus. 



The small Anaptomorphus, from the North American Eocene, 

 has a skull of about the same size as that of the smallest species of 

 Microchcems, but the dental formula is i -H-, c \, p f , m f , and the 

 upper molars are of the tritubercular type. 



The well-known Adapis (Aphelotherium or Palceolemur), of the 

 Upper Eocene of France and England, differs from all existing 

 Lemuroids in possessing four premolars a ; the dental formula being 

 * f c T> P T m f The fourth upper premolar has two outer cusps, 

 and the upper molars (Fig. 333) resemble those of Lepidulemur and 

 Hapalemur, while the lower canine is a well-developed tooth per- 

 forming the usual function of biting against the canine of the upper 

 jaw. The lower incisors have upright, spatulate crowns, as in the 

 true Apes. The skull is said to approximate in contour to that of 

 Propithecus. The typical A. pansiensis is of comparatively small 

 size, but the species of which the upper cheek-teeth are shown in 

 1 One specimen has been seen with only three lower premolars. 



