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Show 1876.] DR. G. E. DOBSON ON MYSTACINA TUBERCULATA. 487 culata, none are more remarkable than the presence of a third phalanx in the middle finger, a character in which it differs from all other species of the family (Emballonuridae) to which it belongs, and agrees with those of a distinct though allied family, the Phyllosto-midae, which are limited to America. The middle finger consists of a metacarpal bone and three phalanges. The first phalanx, instead of being folded (in repose) upon the dorsal surface of the metacarpal bone (as in the other species of Emballonuridae) is flexed downwards, inwards, and forwards upon the inferior surface of the metacarpal, carrying with it the corresponding phalanx of the third finger, which lies folded downwards and forwards, between it and the metacarpal bone ; the second phalanx is folded backwards on the first; and the third phalanx is folded forwards on the second. Being thus reduced by this peculiar folding process into the smallest possible space, the wing is then tucked in beneath the thickened portion of the wing-membrane margining the forearm and side of the body, which sheaths and completely conceals the whole wing. The posterior half of the interfemoral membrane, from the point where the tail perforates it, is rolled upwards and forwards beneath the leathery anterior half. With the wing- and interfemoral membranes thus encased, this species is the most quadrupedal of Bats ; and the peculiar development of the extremities, which I shall now describe, indicates special powers of progression. Fig. a. Fig. b. Thumb and sole of foot of Mystacina tuberculata. The thumb is long, and armed with a large and very acute claw, which has a small talon projecting from its concave surface near the base (fig. a) ; the feet have similarly long and very acute claws ; and at the base of each a similar talon is placed (fig. b). This peculiar basal talon has not been before observed; and I believe it does not occur in any other species of known Bats. A similar talon is found at the base of the claws in the short-tailed Chameleon, Bhampholeon spectrum, which is thus described by Dr. Giinther in his description of that species : - " The tail is so short that it can serve as a prehen- |