| OCR Text |
Show 1876.] MR. G. E. DOBSON ON THE MOLOSSI. 703 great dexterity in quickly changing the direction of their flight, when obliged to double in pursuing their swiftly flying insect prey ; while the extremely expansible lips evidently aid them especially in capturing during rapid flight and in maintaining their hold on the large round-bodied Coleoptera. Of all Bats the Molossi appear especially suited by their peculiar conformation for capturing the most rapidly flying insects, which, no doubt, form the greater portion of their food. Their large and very strong acutely tubercular teeth would enable them to crush with ease the hard armour of the larger Coleoptera. Synopsis of the Genera of Molossi. a. First toe much larger and thicker than the other toes and separable from them ; ears quite separate. «'. Premaxillary bones united; upper incisors very strong, close together in front 1. Cheiromeles, p. 704 b. First and fifth toes much thicker than the other toes; ears united or close together by their inner margins. b'. Premaxillary bones united ; upper incisors close together in front 2. Molossus, p. 705. <*'. Premaxillary bones separate or united by cartilage only; upper incisors separate in front 3. Nyctinomus, p. 716. The genus Cheiromeles is represented by a single species only, which, as I have previously remarked*, appears to be more closely allied to Molossus, which is restricted to America, than to Nyctinomus, of which several species inhabit the same countries with it. The genera Molossus and Nyctinomus are very closely allied, some species, as Molossus glaucinus, Wagner, and M. bonariensis, Peters, forming the connecting links between themf. Nevertheless I retain these genera distinct, as they are convenient for grouping the species, and partly correspond to their geographical distribution, the species of Molossus being confined to America, while those of Nyctinomus are found in both hemispheres. These genera have been divided into several subgenera, which depend on slight differences in dentition and in the form of the ear-conch and tragus. But so many perfectly intermediate forms exist that it is impossible to subdivide Molossus and Nyctinomus, which, indeed, as I have remarked above, may come to be regarded hereafter as subgenera only. Thus M. (Promops) longimanus resembles M. rufus (the representative of the subgenus Molossus) closely in the form of the tragus, and in the obtuse not obliquely truncated muzzle; and M. (Promops) nasutus, relegated to the subgenus Promops on account of its dentition, in all other respects is much more closely allied to M. rufus, with which it agrees in the peculiar form of the antitragus and tragus, and even in the distribution of the fur; while M. rufus, which differs from all other species in dentition, shows its close affinity to the representatives of the sub- * Monograph of the Asiatic Chiroptera, p. 177. 1* Should the discovery of species even more intermediate than these render it necessary at any future time to unite the genera Molossus and Nyctinomus, the former name, which has priority, must be used for the single genus. |
