NO. 9 MAMMALS FROM CAVES IN HAITI MILLER 17 



Curve of upper incisor long, the root of the tooth lying in antorbital 

 foramen; lower incisor terminating beneath m-.,; pm* with two outer 

 reentrant angles, its enamel pattern obviously different from that of 

 the molars ; reentrant folds in upper teeth not very oblique, their slant 

 more than 45° as referred to corresponding alveolar line ; reentrant 

 folds on inner side of lower teeth extending more than halfway across 

 crowns: frontal sinus not sufficiently inflated to produce an obvious 

 swelling over anterior zygomatic root or to encroach on area of ant- 

 orbital foramen or of orbit ; posterior margin of zygomatic process 

 of maxillary lying at or behind level of middle of alveolus of pm\ 

 Opposed inner and outer reentrant angles of all teeth remaining 

 distinct throughout life, the enamel pattern of each tooth 

 entire ; crowns and alveoli of both upper and lower molars 



nearly as long as wide Isolobodon. 



Opposed inner and outer reentrant angles of all teeth becoming 

 confluent in adults, the enamel pattern of each tooth then di- 

 vided into two sections ; crowns and alveoli of both upper and 

 lower molars conspicuously wider than long iplnrirciis. 



The series of mandil:)les includes about 30 specimens in which the 

 breaking through of the opposed enamel folds has not yet taken place. 

 Unfortunately there are no sets of upper teeth representing the same 

 stage. In these immature individuals the enamel pattern of the mandib- 

 ular teeth contains exactly the same elements that are present in the 

 corresponding teeth of Isolobodon. The characteristic peculiarities of 

 crown outline are, however, evident at a very early stage, and, though 

 less pronounced than in the adults, they are sufificient to be diagnostic. 

 In harmony with the shorter tooth crowns of Apluctrcus the enamel 

 folds are narrow as compared with those of Isolobodon, and the re- 

 entrants are more completely filled with cement. The crowns conse- 

 quently tend to have a solid, squarish aspect, while in Isolobodon they 

 are oblong and always with conspicuous angular emarginations. From 

 the mandibular teeth of Plagiodontia those of ApJuctrcns are readily 

 distinguished by the less oblique direction of all the enamel folds, and 

 by the greater length of the outer reentrant, which fold invariably 

 extends more than halfway across the crown, while in Plagiodontia 

 it never reaches the middle of the crown. 



The maxillary teeth have not hitherto been known. Like the man- 

 dibular teeth they contain the same elements that are present in 

 Isolobodon, but these elements are compressed in the axis of the 

 toothrow, and the opposed reentrant folds are confluent in adults, thus 

 splitting the enamel pattern into two sections. The region of breaking 

 through in the maxillary teeth is clearly indicated by irregularities in 

 the enamel outline ; hence it seems probable that in young individuals 

 it will be found that the pattern is not split. 



