Page:Encyclopædia Britannica, Ninth Edition, v. 15.djvu/435

Rh OHIKOl TERA.] MA M M A L I A 413 faces of rocks, or on the trunks of trees growing out over the water, and, owing to the peculiar greyish colour of the fur covering the body and growing in small tufts from the antebrachial membrane, counterfeiting the weathered surfaces of the rocks and the bark of the trees, easily escapes notice. As the shades of evening approach it appears early on the wing, flying close to the surface of the water, and seizing the minute insects that hover over it. Saccoptcryx, i %, antebrachial membrane with a pouch opening on its upper surface, contains six species from Central and South America ; the wing-sac varies in position in different species. It is developed only in the male; in the female it is quite rudimentary. In the adult males of the different species a valvular longitudinal opening is found on the upper surface of the membrane. This opening leads into a small pouch (in some species large enough to hold a pea), the interior of which is lined with a glandular membrane secreting an unctuous substance of a reddish colour with a strong ammoniaeal odour. The presence of this sac in males only indicates that it is a secondary sexunl character analogous to the- shoulder pouches of Epomojriionis, the frontal sacs of Phyllorhina, &c. The next genus Taphozous, including ten species, inhabiting the tropical and subtropical parts of all the eastern hemisphere except Polynesia, forms the second section of this group, distinguished by its cartilaginous prernaxillaries, deciduous pair of upper incisors, and by the presence of four lower incisors only. Most of the species have a peculiar glandular sac (see fig. 80) placed between the I iG. 80. Heads of Tapftoious tongimanus, showing relative duvelopnu-nt of gular sacs in male and female. Dobson, / roc. Zool. Soc., 1873. angles of the lower jaw, a sexual character ; for, while always more developed in males than in females, in some species, although distinct in the male, it is quite absent in the female. An open gular sac is wanting in both sexes in T. melanopogon, but about its usual position the openings of small pores may be seen, the secretion exuding from which probably causes the hairs to grow very long, forming the black beard found in many male specimens of this species. Group III. Dididuri. This is represented by a single genus, Diclidurus, including two species. I), albus, from Central and South America, i, c {, pm f, m f, resembles the species of Taphozous in the form of the head and ears, but, besides other characters, differs from all other Bats in possessing a peculiar pouch, opening on the centre of the inferior surface of the inter- femoral membrane ; the extremity of the tail enters this, and per forates its fund us. Group IV. Noctilioncs. This also is represented by a single genus and two species, Noctilio leporinus and N. dorsatus, i f, pm , from Central and South America. The group connects the family EmballonuridsR with the Phyllostomidse, possessing characters common to both, but also so many remarkable special peculiarities as almost to warrant the formation of a separate family for its reception. The type, N. leporinus of Linnaeus, is a Bat of very curious aspect, with strangely folded lips, erect cutaneous processes on the chin, and enormous feet and claws. The two middle incisors are close to gether, and so large as to con ceal the small outer ones, while in the lower jaw there are but two small incisors. This ap parent resemblance to a Ro dent actually led the great naturalist to remove this FIG. 81. Skull of RMnopoma micro- species from the Bats and phyilum. x 2. Dobson, Monogr. Asiat. place it in his order Glires or Chiropt. Rodents. Similarly the next group Rhinopomata, represented by a single species, JR. microphyllum, might also be elevated into the rank of a family, for it is very difficult to determine its exact affinities, a kind of cross relationship attaching it to the Nycteridsz on the one hand and to this family, in which it is here placed provisionally, on the other. This curious species, distinguished from all other Microcliiroptcra as well by the presence of two phalanges in the index finger as by its remarkably long and slender tail projecting far beyond the narrow interfemoral membrane, in habits the subterranean tombs in Egypt and deserted buildings generally from north-east Africa to Burinah. I Subfamily II. Molossinaa. Tail thick, produced far beyond the posterior margin of the interfemoral membrane (except in Mysta- clna) ; legs short and strong, with well-developed fibulie ; nppor incisors strong. This subfamily includes all the species of Einbal- lonuridse, with short and strong legs and broad feet whereof the first toe (and in most species the fifth also) is much thicker than the others, and furnished with long curved hairs, with well-developed callosities at the base of the thumbs, and with a single pair of large upper incisors occupying the centre of the space between the canines. In all the species the feet are free from the wing- membrane, which folds up very perfectly under the forearm and legs ; the interfemoral membrane is retractile, being movable back wards and forwards along the tail, and this power of varying its superficial extent must confer upon these Bats great dexterity in quickly changing the direction of their flight, as when obliged to double in pursuing their swiftly-flying insect prey, which their extremely expansible lips evidently enable them to secure with ease. Group I. Molossi, Tail produced beyond the posterior margin of the interfemoral membrane. Cheiromcles, i, c , pm ^, m %, hallux much larger than the other toes and separable from them, ears separate, is represented by a single species, C. torquaius, of large size (forearm 3 1 inches) anil very peculiar aspect, inhabiting the Indo- Malayan subregion. This species is nearly naked, a collar only of thinly spread hairs half sur rounding the neck, and is further remarkable for its enormous throat sac and curious nursing pouches. The former consists of&quot; a great semicircular fold of skinforminga deep pouch round the neck beneath, concealing the orifices of large subcutaneous pectoral glands which discharge an oily fluid of, insufferably offensive smell. The nursing pouch is formed on each side by an extension of a fold of skin from the side of the body to the inferior surfaces of the humerus and femur. In the anterior part of this pouch the mamma is placed. For figures of these throat sacs and notes on the use of the nursing pouches see Catal. Chiroptcra, p. 406, pi. xxi. Molossus, i ^ or i, pm ^ or f, upper incisors close together in front, with ten species, is restricted to the tropical and subtropical re gions of the New World. The woodcut of M. glaucinus (fig. 82) exhibits the general physiognomy of the Bats of this genus. M. obscurus, a small species, is very common in tropical America. It inhabits the hollow trunks of palms and other trees, and also the roofs of houses. The males and females live apart (as, indeed, appears to be the case in most if not in all species of Bats). In the hollow trunk of a palm two colonies were FIG. 82. Head of &MGSSUS glaurinu*. discovered, one consisting of from Dobson, Proc. Zool. Sue., 1876. 150 to 200 individuals, exclusively males, while the other was com posed of females with a male here and there among them. Nyctinomus, i % or, pm % or J, upper incisors separate in front, includes twenty-one species, inhabiting the tropical and sub tropical parts of both hemispheres. The lips of the Bats of this genus are even more expansible than in Molossus, in many of the species (as in the woodcut of the head of N. macrotis, fig. 83) showing vertical wrinkles. N. ccstonii, one of the largest species, alone extends into Europe, and has been taken as far north as Switzerland. N. johorcnsis, from the Malay Peninsula, is remark- Fin. 83. Head of Nyctinnmtis ma- able from the extraordinary form crotis. Dobson, Proc. Zool. Soc., of its ears. N. brasilicnsis is nearly 1876 - as common as M. obscurus in tropical America, and extends farther north (California) and south than that species. Group II. Mi/slacinte. Tail perforating the iuterfemoral mem brane, and appearing upon its upper surface. This includes a single genus and species, Mystacina tubcrculafa, a very peculiar form restricted to New Zealand, where, with Chalinolobus tuberculatus, it represents the whole indigenous mammalian fauna of the islands. There are three distinct phalanges in the middle finger ; the greater part of the wing-membrane is exceedingly thin, but a narrow portion along the forearm, the sides of the body, and the legs is remarkably thick and leathery; beneath this thickened portion the wings are folded, and it is evidently analogous to the thickened part of the anterior wings in hemipterous insects and to the elytra of the Coleoptcra. With the wings thus encased, this species is the most quadrupedal of Bats. Other peculiarities of structure are found in the remarkal le form of the claws of the thumbs and toes, which have each a small talon