THE FAMILIES AND GENERA OF 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 bullse 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.” ° 
Specie's 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 A cerodon 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. (bidens.) 
1899. Boneia Matschie, Flederm. des Berliner Mus. fiir 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 co TT 
1 2 1. - 2 3 4 5 6 7 f 2-2 c ’ 1-1’ pm 3-3’ m 2-2 — 32 ' pper lncl " 
a Thomas, Proc. Zool. Soc*. London, 1888, p. 473. 
