and the long and slender tail projecting far beyond the narrow interfemoral membrane, inhabit the subterranean tombs in Egypt and deserted buildings generally from north-east Africa to Burma and Sumatra.
|Fig. 16.—Skull of Mouse-tailed Bat|
(Rhinopoma microphyllum). ×2. (From Dobson.)
The last group, according to the system adopted by Prof. Max Weber, is that of the Vespertilionidae, which includes such typical bats as the pipistrelle, the noctule, and the long-eared species. By Mr G.S. Miller the first section of theTypical bats. family—Natalinae—is regarded as of family rank, while the last section, or Molossinae, is included by Dr G. E. Dobson in the Emballonuridae, from the typical forms of which its members differ widely in tail-structure. In this extended sense the family, which has a cosmopolitan distribution, may be defined as follows:—The nostrils are normal and without a nose-leaf. The ethmoturbinal bones of the nasal chamber are involuted. The palatine processes of the premaxillae do not form a suture. The ear is mostly large, with a tragus. The middle finger (except in Thyroptera) has two phalanges. The fibula is usually rudimentary. The tail is long and does not perforate the interfemoral membrane. The incisors are generally 2 or 1, but may be reduced to 1 in the Molossinae.
|Fig. 17.—Head of Chilonatalus micropus. ×2. (From Dobson.)|
In the first subfamily, Natalinae, which is exclusively tropical American, the other upper incisors are separated from one another and from the canines; palatine processes of the premaxillae are at least partially developed; and the dental formula is i. 2, c. 1, p. (2 or 3)/3, m. 3. In general appearance these bats recall the more typical Vespertilionidae, although the form of the muzzle is suggestive of the Mormopsinae among the Phyllostomatidae. Again, while the form of the skull is vespertilione, the relation of the vomer to the front end of the premaxillae is of the phyllostomine type. The molars and incisors are likewise vespertilione, whereas the premolars are as distinctly phyllostomine. Finally, while the third, or middle, finger normally has two phalanges, as in typical Vespertilionidae, the second of these is elongated and in Thyroptera divided into two, as in Phyllostomatidae.
|Fig. 18.—Suctorial Disks in Thyroptera tricolor, a, side, and b, concave surface, of thumb disk;|
c, foot with disk, and calcar with projections (all much enlarged). (From Dobson.)
The first two genera, Furipterus and Amorphochilus, each have a single species, the latter being distinguished from the former by the wide separation of the nostrils and the backward prolongation of the palate. In both the crown of the head is elevated, the thumb and first phalange of the middle finger are very short, and the premolars are 2. The same elevation of the crown characterizes the genera Natalus and Chilonatalus (fig. 17), in which the premolars are 3: in general appearance these bats are very like the Old World vespertilionine genus Cerivoula, except for the short triangular tragus. Lastly, Thyroptera includes two species distinguished by an additional phalange in the middle finger and by accessory clinging-organs attached to the extremities. In Thyroptera tricolor, i. 2, p. 3, from Brazil, these have the appearance of small, circular, stalked, hollow disks (fig. 18), resembling miniature sucking-cups of cuttle-fishes, and are attached to the inferior surfaces of the thumbs and the soles of the feet. By their aid the bat is able to maintain its hold when creeping over smooth vertical surfaces.
|Fig. 19.—Head of Scotophilus|
emarginatus. (From Dobson.)
The second or typical subfamily, Vespertilioninae, includes all the remaining members of the family with the exception of the aberrant Molossinae. The upper incisors are in proximity to the canines; the premaxillae widely separated; the ears medium or large; the dental formula is i. 2 (or 1), c. 1, p. 3 ( 2, 2, or 1), m. 3; and the fibula very small and imperfect. All the members of this large cosmopolitan group are closely allied, and differ chiefly by external characters. They may be divided into subgroups. In the first of these, the Plecoteae, of which the long-eared bat (Plecotus auritus) is the type, the crown of the head is but slightly raised above the face-line, the upper incisors are close to the canines, and the nostrils are margined behind by grooves an the upper surface of the muzzle, or by rudimentary nose-leaves; the ears being generally very large and united. Of the six genera, Plecotus, with i. 2, p. 2, has three species:—one the long-eared European bat referred to above; P. macrotis, restricted to North America, is distinguished by the great size of the glandular prominences of the sides of the muzzle, which meet in the centre above and behind the nostrils; the third species being also American. The second, Barbastella, with i. 2, p. 2, distinguished by its dentition and by the outer margin of the ear being carried forwards above the mouth and in front of the eye, includes the European barbastelle bat, B. barbastellus, and B. darjelingensis from the Himalaya. Otonycteris, i. 1, pm., 1, connecting this group with the Vespertilioneae, is represented by O. hemprichii, from North Africa and the Himalaya, and an Arabian species. The next two genera are distinguished by the presence of a rudimentary nose-leaf: Nyctophilus, i. 1, p. 1, with three species from Australasia; and Antrozous, i. 1, p. 1, distinguished from all the other members of the subfamily by having but two lower incisors, and from other Plecoteae by the separate ears; the two species inhabit California. The sixth genus, Euderma, is also represented by a Californian species.
|Fig. 20.—Head of Cerivoula hardwickei. (From Dobson.)|
The second group Vespertilioneae, with about thirteen genera, includes the great majority of the species; and a large number of these may be classed under Vespertilio, which is divisible into subgenera, differing from one another in the number of premolars, and often ranked as separate genera. One group is represented by V. (Histiolus) magellanicus, a species remarkable for its extreme southern range, its relatives being also South American. A second group, with p. 1, includes the British serotine, V. (Eptesicus) serotinus, of Europe and northern Asia, and represented in North America by the closely allied V. (E.) fuscus. In the typical group, which includes the Old World V. murinus, one species, V. borealis, ranges to the Arctic circle. The European noctule, V. (Pierygistes) noctula, and Leisler’s bat, V. (P.) leisleri, represent another group; and the common pipistrelle, V. (Pipistrellus) pipistrellus, yet another, with p. 2. The only other group that need be mentioned is one represented by the North American V. (Lasionycteris) noctivagans, with p. 2. The African Läephotes, the Chinese Ia, and the Papuan Philetor are allied genera, each with a single species. Chalinolobus and Glauconycteris have the same general dental character as Vespertilio, but are distinguished by the presence of a lobe projecting from the lower lip near the gape; the former, with p. 2, is represented by five Australasian species, one of which extends into New Zealand; while the latter, with p. 1, is African. The species of Glauconycteris are noticeable for their peculiarly thin membranes traversed by distinct reticulations and parallel lines. Scotophilus, with i. 1, p. 1, includes several species, restricted to the tropical and subtropical regions of the eastern hemisphere, though widely distributed within these limits. These bats, though approaching certain species of Vespertilio in many points, are distinguished by the single (in place of two) pair of unicuspidate upper incisors separated by a wide space and placed close to the canines, by the small transverse first lower premolar crushed in between the canine and second premolar, and, generally, by their conical, nearly naked, muzzles and thick leathery membranes. S. temmincki is the commonest bat in India, and appears often before the sun has touched the horizon. S. gigas, from equatorial Africa, is the largest species. Nycticejus, with the same dental formula as Scotophilus, is distinguished, by the first lower premolar not being crushed in between the adjoining teeth, and the comparatively greater size of the last upper molar. It includes only the North American N. humeralis (crepuscularis), a bat scarcely larger than the pipistrelle. The hairy-membraned bats of the genus Lasiurus (Atalapha), with i. 1, p. 2 or 1, are also limited to the New World, and generally characterized by the interfemoral membrane being more or less covered with hair and by the peculiar form of the tragus, which is expanded above and abruptly curved inwards. In those species which have two upper premolars the first is extremely small and internal to the tooth-row. The genus, which is divided into Lasiurus proper and Dasypterus, is further characterized by the presence of four teats in the female, and by the general production
- Bull. Amer. Mus. Nat. Hist. vol. xii. (1899).