OCR Text |
Show 872 MR. G. E. DOBSON ON MYXOPODA AURITA. [Nov. 5, Crown of the head but slightly raised above the face-line ; muzzle obliquely truncated, in general form closely resembling that of the species of the genus Chilonycteris; for the nostrils open widely apart by similar circular sharply defined margins, and the lower lip is also papillate and reflected outwards, though not so broadly, and it has not a thin free margin; the obtuse extremity of the rather long muzzle projects in front considerably beyond the lower lip. Ears very large, much longer than the head, in general outline like those of Vespertilio murinus ; but the inner margin commences in a small lobe projecting downwards ; in the usual position of the tragus, or slightly in front of it, there is an irregularly square lobe continuous above with the keel of the ear-conch; opposite this, on the outer side of the concave surface of the conch, is a mushroom-shaped process consisting of a short stalk supporting a broad flat reniform expansion; the outer margin of the conch terminates near the angle of the mouth. Thumb with an ill-developed claw ; but the whole of the inferior surface of its metacarpal and phalangeal bones supports a large flat horseshoe-shaped pad, more than 0"*2 inch in diameter, of which the circular margin is directed forwards and slightly notched in front; this pad, though considerably larger than that occupying the same position in Thyroptera tricolor, does not form nearly so perfect a clinging-organ as in that species; for it is quite sessile, without a trace of a peduncle, and its surface is flat, like the thumb-pad of Vesperugo pachypus, with which it is evidently homologous. The feet have also adhesive pads; but, while resembling closely those of the thumbs in structure and external form, they differ in being much smaller, and so agree rather with those of Thyroptera tricolor than with Vesperugo pachypus. The metacarpal bone of the index finger is well developed, being nearly as long as that of the third finger, but there are no distinct phalanges; the third finger has three phalanges, of which the first and second are nearly equal in length. The tail projects beyond the posterior margin of the interfemoral membrane as in Thyroptera tricolor, but to a much greater extent, the free portion being nearly equal to the tibia in length; the calcanea are almost as long as the tibiae ; the very narrow post-calcaneal lobe is notched or toothed near the foot. As in Thyroptera tricolor, the toes are united as far as the base of the claws, and have each two phalanges, and the wing-membrane extends almost to the base of the claws. -r. .... T 2-2 1-1 3-3 3-3 Dentition.-Inc. -j-, c. -j-^, pm. g^, m. g^, Upper incisors short, in pairs, placed close to the canines; the outer incisor, on each side, small, conical, and acutely pointed, but much larger than tbe inner one, which lies close to it and is hardly visible without the aid of a lens; lower incisors short and blunt, in the direction of the jaws; first and second upper premolars very short, the third exceeding the molars in vertical extent; second lower premolar minute, in the tooth-row, the first premolar slightly |