THE FAMILIES AND GENEKA OP BATS. 61 



Characters. — In general like Pteropus, but skull with broader, 

 nearly parallel-sided rostrum, more upwardly directed orbits, and 

 high sagittal crest, somewhat obscuring tubularity of occipital re- 

 gion, and both canines and cheek teeth conspicuously several-cusped. 

 Except as noted, the skull does not differ particularly from that of 

 Pteropus. The posterior portion of brain case is distinctly tubular 

 and so deflected that the alveolar line, projected backward, passes 

 just below root of zygoma. Premaxillaries rather shorter and broader 

 than in Pteropus, and in contact for about 2 mm. anteriorly. 

 Audital bullae as in Pteropus. Dental formula as in Pteropus, but 

 pm 2 larger and apparently persistent. " Upper incisors with broad 

 posterior ledges. Upper canines short vertically, enormously thick 

 antero-posteriorly, each with one stout secondary cusp halfway up its 

 posterior edge, and two smaller postero-internal basal cusps. Pre- 

 molars and molars short and broad, their anterior and posterior basal 

 ledges so developed and their main cusps so conical as to destroy all 

 the appearance of longitudinal grooving characteristic of the genus 

 Pteropus. Lower incisors extremely disproportionate in size, the 

 outer not less than about twenty times the bulk of the inner. Canines 

 very short vertically, with a simple posterior basal ledge. Cheek 

 teeth markedly cuspidate, the general longitudinal grooving quite 

 obliterated. Posterior premolar and first molar each with three high 

 anterior cusps, and a low posterior basal ledge." a 



Species examined. — Pteralopex atrata Thomas. 



Remarks. — The dentition of Pteralopex represents one of the ex- 

 treme phases of that tendency to develop secondary cusps, which 

 appears to be everywhere latent in the Pteropidse. The stages through 

 which it has passed are indicated in the genera Acerodon and Des- 

 malopex. The much-reduced inner mandibular incisor, the broad- 

 ened rostrum, and the complete, strongly upturned orbits are also 

 highly specialized characters. 



Genus BONEIA Jentink. 



1879. Boneia Jentink, Notes from the Leyden Museum, I, p. 117. (Hdens.) 

 1899. Boneia Matsohie, Flederm. des Berliner_Mus. fur Naturk., p. 69. 



Type-species. — Boneia bidens Jentink. 

 Geographic distribution. — Celebes. 

 Number of forms. — Two species are now known. 

 Characters. — Like Pteropus, but with a distinct tail; only 1-1 up- 

 per incisors ; cheek teeth with crowns much flattened. Dental formula : 



- 2 -. 1. - 2 3 4 5 6 - . 1-1 1-1 3-3 2-2 on TT 



12-. 1.-984 5-67 * 2=2 °' 1=1' ^ 3=3' m 2=2 = 32< U PP er lncl " 



a Thomas, Proc. Zool. Soc. London, 1888, p. 473. 



