NO. 9 MAMMALS FROM CAVES IN HAITI MILLER I9 



instead of ranginj^ from about 48 to 54 mm. ; mandibular toothrow 

 usually less than 18 mm. instead of ranging from about 18.5 to 

 20.5 mm. Portion of mandible in front of cheekteeth relatively shorter 

 and more abruptly curved than in P. hylcpum. 



Measurements. — From five jaws which may be regarded as adult 

 I am able to obtain the following measurements : length of mandible 

 from articular process, 39.6, 39 ±, — , — , — , length of symphysis, 

 18.0, 18 ±, 17 ±. 17.6, — ; diastema, 9.0, 9.4, g±, 8.8, 9.2; depth 

 from alveolar margin to lowermost point of symphysis, 1 1.2, 11 .2, 1 1.2, 

 10.8, 11.6; mandibular toothrow (alveoli), 16.2, 16.0, 15.8, 16.0, 15.6; 

 transverse diameter of iiii (grinding surface), 4.5, 4.5, 4.5, 4.2, 4.4. 

 The same measurements in a mandible of F. hylcemn which appears 

 to be of exactly corresponding age (No. 239886) : length from articu- 

 lar process, 48 ; symphysis, 21.6 ; diastema, 1 1.4 ; depth 13.0 ; toothrow, 

 18.6; width of nil, 5-3- 



Specimens examined. — Fifteen mandibles, all imperfect. Four of 

 these came from the group of caves near St. Michel, the others were 

 found in the crooked cave near the Atalaye plantation. 



Remarks. — The small Plagiodontia from the St. Michel caves differs 

 conspicuously from the associated large P. cediiwi in size and in the 

 longitudinally compressed cheekteeth. Its affinities are obviously with 

 P. hylceum of the Samana Bay region, the only member of the genus 

 known to be now living. At first sight the jaws of Plagiodontia 

 spelceum might be mistaken for immature specimens of F. hylceum, 

 but when comparison is made lietween individuals in corresponding 

 stages of development (as indicated in immature individuals by the 

 eruption of the second and third molars, and in young adults by the 

 gradual disappearing of porousness and surface wrinkling of the bone 

 on the lower side of the jaw beneath the roots of these teeth) the 

 differences between the two species become obvious. 



HEXOLOBODON gen. nov. 



Plate 3, tigs. I, la, lb 



Type. — Hcxolobodon phcnax sp. nov. 



Characters. — So far as known most like Geocapromys, but differing 

 as follows : cheekteeth with roots becoming closed at or soon after 

 the stage when the crowns are worn flat ; root of lower incisor passing 

 beneath root of m-^ and terminating, in fully adult individuals, on outer 

 side of toothrow beneath the floor of the groove which separates the 

 alveolus of 7W3 from the base of the coronoid process; pm^ (pi. 3, 

 fig. la) with only two reentrant angles on inner side (as in Capromys) ; 



