Chapter XIII: The Order Chiroptera (2)

_Fossil Vespertilionidæ._—It is not improbable that _Vesperugo_ is represented in the Upper Eocene of the Paris basin by _V. parisiensis_, which appears to be allied to _V. serotina_, although it has been regarded by some writers as generically distinct, under the name of _Nyctitherium_. _Vesperugo_ (_Nyctitherium_) also occurs in the Bridger Eocene of the United States; _Nyctilestes_ from the same deposits being an allied extinct genus. A number of European Miocene species have been referred to _Vespertilio_, but the term in these cases must be used in a somewhat wide sense. _Vespertiliavus_, of the Phosphorites of Central France, differs from _Vespertilio_ in the proportions of its premolars.

_Section_ EMBALLONURINA.

Tail perforating the interfemoral membrane and appearing on its upper surface, or produced considerably beyond the truncated membrane; the middle pair of upper incisors generally large and close together.

_Family_ EMBALLONURIDÆ.

First phalanx of the middle finger folded (in repose) on the dorsal surface of the metacarpal bone (except in _Noctilio_ and _Mystacops_). Nostrils opening by simple circular or valvular apertures at the extremity of the muzzle, not surrounded or margined by foliaceous cutaneous appendages; tragus distinct.

The _Emballonuridæ_ are generally easily distinguished by the peculiar form of the muzzle, which is obliquely truncated, the nostrils projecting more or less in front beyond the lower lip; by the first phalanx of the middle finger being folded in repose forwards on the upper surface of the metacarpal bone; by the tail, which either perforates the interfemoral membrane or is produced far beyond it; and by the upper incisors, which are generally a single pair separated from the canine and also in the middle line. The family is cosmopolitan like the _Vespertilionidæ_, but rarely extends north or south of the thirtieth parallel of latitude.

Subfamily =Emballonurinæ=.—Tail slender, perforating the interfemoral membrane, and appearing upon its upper surface, or terminating in it; legs long, fibula very slender; upper incisors weak.

In the _Furipterine_ division the tail terminates in the interfemoral membrane; the crown of the head is greatly elevated above the face-line; the thumb and first phalanx of the middle finger are very short; and the dentition is _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total 38.

Represented by two genera, _Furipterus_[613] and _Amorphochilus_,[614] each including one species of peculiar aspect; the latter distinguished from the former by the widely separated nostrils and the great extension backwards of the bony palate. Habitat South America.

In the typical or _Emballonurine_ division part of the tail is included in the basal half of the interfemoral membrane, the remaining part passing through and appearing upon its upper surface; the crown of the head is slightly elevated; the pollex and first phalanx of the middle finger are moderately long; and the number of the premolars is always ²⁄₂.

_Emballonura._[615]—Incisors ²⁄₃. Extremity of the muzzle more or less produced beyond the lower lip, forehead flat. Contains some five species, inhabiting islands from Madagascar through the Malay Archipelago to the Navigators’ Islands.

_Coleüra._[616]—Incisors ¹⁄₃. Extremity of the muzzle broad, forehead concave. Has two species from East Africa and the Seychelles Islands.

_Rhynchonycteris._[617]—This genus is distinguished from _Coleüra_ by the much-produced extremity of the muzzle. The single species, _R. naso_, from Central and South America, is very common in the vicinity of streams throughout the tropical parts of these countries; it is usually found during the day resting on the vertical faces of rocks, or on the trunks of trees growing over the water, and, owing to the peculiar grayish colour of the fur covering the body and growing in small tufts from the antebrachial membrane, so as to counterfeit the weathered surfaces of rocks and the bark of 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.

_Saccopteryx._[618]—Incisors ¹⁄₃. Antebrachial membrane with a pouch opening on its upper surface. This genus contains six species from Central and South America. In the adult males a valvular longitudinal opening is found on the upper surface of the membrane, varying in position in different species. 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 ammoniacal odour. The presence of this sac only in males indicates that it is a secondary sexual character analogous to the shoulder-pouches of _Epomophorus_ and the frontal sacs of _Hipposiderus_. It is quite rudimentary in the females.

_Taphozous._[619]—Incisors ¹⁄₂; upper pair deciduous. This genus, represented by some ten species, inhabiting the tropical and subtropical parts of all the eastern hemisphere except Polynesia, forms the second group of this division, distinguished by the cartilaginous premaxillaries, deciduous upper incisors, and the presence of only two lower incisors. Most of the species have a peculiar glandular sac (Fig. 313) placed between the angles of the lower jaw. This is 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.

In the _Diclidurine_ division there is but a single genus, represented by two species.

_Diclidurus._[620]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; total 32. Both species are from the Neotropical region, the typical _D. albus_ ranging as far north as Central America. This Bat 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 interfemoral membrane; the extremity of the tail enters this, and perforates its fundus.

The _Noctilionine_ division is likewise represented only by a single genus, with two species. This genus connects the present with the following family, 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.

_Noctilio._[621]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total 28. The two species _N. leporinus_ and _N. albiventer_ inhabit Central and South America. The typical _N. leporinus_ is a Bat of very curious aspect, with strangely folded lips, erect cutaneous processes on the chin, and enormous feet and claws. The first upper incisors are close together, and so large as to conceal the small outer ones, while in the lower jaw there is one pair of small incisors. This apparent resemblance to a Rodent actually led Linnæus to remove this species from the Bats and place it in the Rodents. This Bat is remarkable for feeding on fish—a circumstance which has only recently been fully authenticated.

The remaining genus of this subfamily is regarded as representing another division, which may be known as the _Rhinopomatine_ division.

_Rhinopoma._[622]—This genus, represented by the single species _R. microphyllum_, might also be elevated to the rank of a family, for it is difficult to determine its exact affinities, a kind of cross relationship attaching it to the _Nycteridæ_ on the one hand and to this family, in which it is here placed provisionally, on the other. This species, distinguished from all other Microchiroptera 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, inhabits the subterranean tombs in Egypt and deserted buildings generally from North-East Africa to Burma.

Subfamily =Molossinæ=.—Tail thick, produced far beyond the posterior margin of the interfemoral membrane (except in _Mystacops_); legs short and strong, with well-developed fibula; upper incisors strong. This subfamily includes all the species of _Emballonuridæ_ 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), well-developed callosities at the base of the thumbs, and 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 perfectly under the forearm and legs; the interfemoral membrane is retractile, being movable backwards 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 swift insect prey, which their extremely expansible lips evidently enable them to secure with ease. Like the preceding subfamily, the genera may be arranged in divisions, of which there are two.

The _Molossine_ division is characterised by the production of the tail beyond the posterior margin of the interfemoral membrane; it includes three genera.

_Chiromeles._[623]—Dentition: _i_ ¹⁄₁, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total 26. Hallux much larger than the other toes and separable from them, ears separate. This genus is represented by a single species, _C. torquatus_, of large size (forearm 3·1 inches) and peculiar aspect, inhabiting the Indo-Malayan sub-region. This Bat is nearly naked, a collar only of thinly spread hairs half surrounding the neck; and is further remarkable for its enormous throat-sac and curious nursing-pouches. The former consists of a great semicircular fold of skin forming a deep pouch round the neck beneath, and 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 mammæ are placed.

_Molossus._[624]—Dentition: _i_ ¹⁄₁₋₂, _c_ ¹⁄₁, _p_ ¹⁻²⁄₁, _m_ ³⁄₃; total 24 or 28. Upper incisors close together in the middle line. There are some ten species, restricted to the tropical and subtropical regions of the New World. The woodcut of the head of _M. glaucinus_ (Fig. 315) 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 discovered, one consisting of from 150 to 200 individuals, exclusively males, while the other was composed almost entirely of females.

_Nyctinomus._[625]—Dentition: _i_ ¹⁄₃₋₂, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃; total 32 or 28. Upper incisors separated in the middle line. The genus contains about twenty-five species, inhabiting the tropical and subtropical 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. 316) showing vertical wrinkles. _N. tæniotis_, one of the largest species, alone extends into Europe, and has been taken as far north as Switzerland. _N. johorensis_, from the Malay Peninsula, is remarkable from the extraordinary form of its ears. _N. brasiliensis_ is nearly as common as _Molossus obscurus_ in tropical America, and extends farther north (California) and south than that species.

In the _Mystacopine_ division the tail perforates the interfemoral membrane and appears upon the upper surface.

_Mystacops._[626]—This genus includes only _M. tuberculatus_ of New Zealand, where, together with _Chalinolobus tumorio_, 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. With the wings thus encased, this species is the most quadrupedal of Bats. Other peculiarities of structure are found in the remarkable form of the claws of the thumbs and toes, which have each a small talon projecting from its concave surface near the base, also in the sole of the foot and inferior surface of the leg, as shown in Fig. 317. The plantar surface, including the toes, is covered with soft and very lax integument deeply wrinkled, and each toe is marked by a central longitudinal groove with short grooves at right angles to it. The lax wrinkled integument is continued along the inferior flattened surface of the ankle and leg. These peculiarities appear to be related to climbing habits in the species.

_Fossil Emballonuridæ._—In the cavern-deposits of Madras remains of the existing _Taphozous saccolæmus_ are not uncommon; while in the corresponding beds of Brazil bones of a _Molossus_, probably referable to _M. temmincki_, now inhabiting the same region, are met with. It has been suggested that remains from the Upper Eocene Phosphorites of Central France may indicate the existence of the genus _Taphozous_ at that early epoch.

_Family_ PHYLLOSTOMATIDÆ.

Middle finger with three well-developed bony phalanges; first phalanx of the middle finger short; nostrils in the front part of the cutaneous nasal appendages, or opening by simple apertures at the extremity of the muzzle; chin with warts or erect cutaneous ridges; premaxillæ well developed, united in front.

The members of this family are readily distinguished by the third phalanx in the middle finger, associated either with distinct cutaneous nasal appendages, or with well-developed first upper incisors, or with both. Unlike the _Rhinolophidæ_, their eyes are generally large; and the tragus is well developed, maintaining almost the same form throughout the species, however much the other parts of the body may vary. The fur is of a dull colour, and the face and back (in the _Stenodermatine_ division especially) are often marked with white streaks, as in the _Pteropodidæ_, of which these Bats take the place in the western hemisphere. A few species, probably all those with the tail and interfemoral membrane well developed, feed principally on insects, while the greater number of the species of the _Vampirine_ and _Glossophagine_ divisions appear to live on a mixed diet of insects and fruits; and the _Desmodontine_ division, of which two species only are known, are true blood-suckers, and have their teeth and intestinal tract specially modified in accordance with their habits. The family is restricted to the tropical and subtropical parts of Central and South America.

Subfamily =Chilonycteriinæ=.—Nostrils opening by simple apertures at the extremity of the muzzle in front, not margined by a distinct nose-leaf; chin with expanded leaf-like appendages. It includes two genera.

_Chilonycteris._[627]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total 34. The crown of the head is moderately elevated above the facial line, and the basicranial axis is almost in the same plane as the facial. There are about half a dozen species.

_Mormops._[628]—The two species of this genus are distinguished from _Chilonycteris_ by the great elevation of the crown of the head above the line of the face, as well as by the basicranial plane being nearly at right angles to the facial. Both species are noticeable for their peculiar physiognomy, as is shown in the accompanying woodcut (Fig. 318).

Subfamily =Phyllostomatinæ=.—Nostrils opening on the upper surface of the muzzle, the nasal apertures more or less surrounded or margined by well-developed cutaneous appendages, forming a distinct nose-leaf; chin with warts. The numerous genera, most of which can only be mentioned here by name, may be arranged under four divisions.

In the first or _Vampirine_ division the muzzle is long and narrow in front; the distance between the eyes is generally less than, rarely equal to, that from the eye to the extremity of the muzzle; the nose-leaf is well developed, horse-shoe shaped in front, and lanceolate behind; interfemoral membrane well developed; tail generally distinct, rarely absent; inner margin of the lips not fringed. The dentition is: _i_ ²⁄₂₋₁, _c_ ¹⁄₁, _p_ ²⁄₂₋₃, _m_ ³⁄₃; total 32. The cusps of the upper molars are usually well developed, and arranged in a W. Nearly all the species of this division appear to be insectivorous, so that the name applied to them must not be considered as having any relation to their habits. _Vampyrus spectrum_, a large Bat inhabiting Brazil, of forbidding aspect, which was long considered by naturalists to be sanguivorous in its habits, and named accordingly by Geoffroy, has been shown by the observations of modern travellers to be mainly frugivorous, and is considered by the inhabitants of the countries in which it is found to be perfectly harmless. It is the largest Bat in America, the length of the forearm being 4·2 inches. _Otopterus waterhousei_ appears to prey occasionally on small species of Bats, like _Megaderma lyra_ of the eastern hemisphere, which it resembles in many respects.

_Lonchorhina_,[629] _Otopterus_,[630] _and Dolichophyllum_.[631]—These three genera are characterised by the tail continuing to the hinder margin of the interfemoral membrane. _Lonchorhina_ is represented by the single species _L. aurita_, in which the nose-leaf is much elongated, and the ear-conch and tragus are unusually large.

_Vampyrus_,[632] _etc._—In all the remaining genera of this division the tail perforates the interfemoral membrane, so as to appear upon its upper surface. These genera are _Vampyrus_, _Lophostoma_, _Micronycteris_,[633] _Trachyops_, _Phylloderma_, _Phyllostoma_, _Anthorhina_,[634] _Mimon_, _Hemiderma_[635] and _Rhinophylla_; all, with the exception of the last, being distinguished from one another chiefly by the form of the skull and the presence or absence of the second lower premolar. _Trachyops_, _Phylloderma_, and the three last-named genera are each represented by a single species. _Phyllostoma hastatum_, in which the forearm has a length of 3·2 inches, and next in point of size to _Vampyrus spectrum_, is a well-known species in South America; _P. elongatum_ (Fig. 319) differs in its smaller size and much larger nose-leaf. _Hemiderma brevicauda_ is a small species, which forms a connecting link between this and the next division. _Rhinophylla pumilio_, the smallest known species of the family, is further distinguished by the narrowness of its molars, which do not form W-shaped cusps, and by the very small size of the last upper molar; characters connecting it with the _Stenodermatine_ division.

In the second or _Glossophagine_ division of the subfamily the muzzle is long and narrow; the tongue remarkably long and extensible, much attenuated towards the tip, and beset with very long filiform recurved papillæ; lower lip with a wide groove above, and in front margined by small warts; nose-leaf small; tail short or absent. Dentition: _i_ ¹⁄₁, _c_ ²⁄₂, _p_ ²⁻³⁄₃₋₂, _m_ ²⁄₃₋₂; teeth very narrow; molars with narrow W-shaped cusps, sometimes indistinct or absent; lower incisors very small or deciduous.

The ten species included in this division are arranged under seven genera,[636] distinguished principally by differences in the form and number of the teeth and the presence or absence of the zygomatic arch. The form and position of the upper incisors are extremely variable. In _Glossophaga_ and _Phyllonycteris_ the upper incisors form, as in the _Vampyrine_ division, a continuous row between the canines; in _Monophylla_ and _Leptonycteris_[637] they are separated into pairs by a narrow interval in front; while in _Lonchoglossa_, _Glossonycteris_, and _Chœronycteris_ they are widely separated and placed in pairs near the canines. In the first four genera the lower incisors are present (at least up to a certain age), while in the last three they are deciduous even in youth. The zygomatic arch is wanting in _Phyllonycteris_, _Glossonycteris_, and _Chœronycteris_.

The typical species is _Glossophaga soricina_, which so closely resembles _Hemiderma brevicauda_, both in external form and dentition, that it has frequently been confounded with it. Its long fimbriated tongue, which it possesses in common with other species of the division, led Spix to describe it as a blood-sucker, believing that this organ was used to increase the flow of blood. This view is, however, without foundation, and from later observations it is evident that the peculiarly shaped tongue is used by the animal to lick out the pulpy contents of fruits having hard rinds. The food of the species of this division appears to consist of both fruit and insects, and the long tongue may also be used for extracting the latter from the deep corollæ of certain flowers. This type of tongue is shown in the woodcut of the head of _Chœronycteris_ (Fig. 320); and it is paralleled among the Megachiroptera by the Carponycteriine _Pteropodidæ_.

The _Stenodermatine_ division is characterised by the muzzle being very short and generally broad in front, the distance between the eyes nearly always exceeding (rarely equal to) that from the eye to the extremity of the muzzle; nose-leaf short, horse-shoe shaped in front, lanceolate behind (except in _Brachyphylla_ and _Centurio_); interfemoral membrane always concave behind; tail none; inner margin of the lips fringed with conical papillæ. Dentition: _i_ ²⁄₂₋₁, _p_ ²⁄₂, _m_ ³⁻²⁄₃₋₂; the number of the molars being either ³⁄₃, ²⁄₃, or ²⁄₂ in different species; premolars and molars very broad (except in _Sturnira_), the latter with concave or flat crowns margined externally by raised cutting-edges. Although the members of this division are usually distinguished from those of the Vampirine division by the peculiar shortness and breadth of the muzzle and the form of the molars, yet certain species of the latter closely resemble those of the former in external appearance, agreeing almost absolutely in the form of the nose-leaf, of the ears and tragus, and of the warts on the chin. These resemblances indicate that, while the form of the teeth and jaws has become modified to suit the nature of the food, the external characters, being but slightly affected by this cause, have remained much the same. The food of these Bats appears to be wholly or in great part fruit. The twenty species have been grouped into nine genera, distinguished by the form of the skull and teeth. _Artibeus_, with six species, includes the well-known frugivorous Bat, _A. perspicillatus_. Waterton believed that _A. planirostris_, a common Bat in British Guiana, usually found in the roofs of houses, and now known to be frugivorous, was the true blood-sucking Vampire. _Stenoderma achradophilum_, found in Jamaica and Cuba, associated with _Artibeus perspicillatus_, from which it is scarcely distinguishable externally except by its much smaller size, differs altogether in the absence of the horizontal plate of the palatal bones. _Sturnira lilium_, while agreeing with the above in the form of the nose-leaf and ears, differs from all the species of the family in its longitudinally-grooved molars, which resemble those of the _Pteropodidæ_ more closely than those of any other Bats; and the presence of tufts of long differently coloured hairs over glands in the sides of the neck shows another common character still more remarkable, which can scarcely be considered the result of adaptive change. _Centurio senex_ is the type of a genus distinguished from _Stenoderma_ and other genera of this division by the absence of a distinct nose-leaf; its facial aspect, as shown in Fig. 321, is altogether bizarre.

In the last or _Desmodont_ division the muzzle is conical and short; there is a distinct nose-leaf; the interfemoral membrane is very short; and the tail is wanting. Dentition: _i_ ¹⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ¹⁻⁰⁄₁₋₀; total 24 or 20. Upper incisors very large, trenchant, occupying the whole space between the canines; premolars very narrow, with sharp-edged longitudinal crowns; molars rudimentary or wanting; stomach greatly elongated, intestiniform. There are only two genera, the single species of each of which are the true blood-sucking Vampires. They appear to be confined chiefly to the forest-clad parts, and their attacks on men and other warm-blooded animals were noticed by some of the earliest writers. Thus Peter Martyr (Anghiera), who wrote soon after the conquest of South America, says that in the Isthmus of Darien there were Bats which sucked the blood of men and cattle when asleep to such a degree as to kill them. Condamine, a writer of the eighteenth century, remarks that at Borja (Ecuador) and in other places they had entirely destroyed the cattle introduced by the missionaries. Sir Schomburgk relates that at Wicki, on the river Berbice, no fowls could be kept on account of the ravages of these creatures, which attacked their combs, causing them to appear white from loss of blood. Although these Bats were known thus early to Europeans, the species to which they belonged were not determined until about sixty years ago, several of the large frugivorous species having been wrongly set down as blood-suckers and named accordingly; and it fell to the lot of Darwin to determine at least one of the blood-sucking species, the following being his account of the circumstances under which the discovery of the sanguivorous habits of _Desmodus rufus_ was made: “The Vampire Bat is often the cause of much trouble by biting the horses on their withers. The injury is generally not so much owing to the loss of blood as to the inflammation which the pressure of the saddle afterwards produces. The whole circumstance has lately been doubted in England; I was therefore fortunate in being present when one was actually caught on a horse’s back. We were bivouacking late one evening near Coquimbo, in Chili, when my servant, noticing that one of the horses was very restive, went to see what was the matter, and, fancying he could detect something, suddenly put his hand on the beast’s withers and secured the Vampire.”

These Bats present, in the extraordinary differentiation of the manducatory and digestive apparatus, a departure from the type of other members of the family unparalleled in any of the other orders of Mammalia, standing apart from all other mammals as being fitted only for a diet of blood, and capable of sustaining life upon that alone. Travellers describe the wounds inflicted by the large sharp-edged incisors as similar to those caused by a razor when shaving: a portion of the skin being shaved off and a large number of severed capillary vessels thus exposed, from which a constant flow of blood is maintained. From this source the blood is drawn through the exceedingly narrow gullet—too narrow for anything solid to pass—into the intestine-like stomach, whence it is probably gradually drawn off during the slow process of digestion, while the animal, sated with food, is hanging in a state of torpidity from the roof of a cave or the inner side of a hollow tree.

_Desmodus._[638]—No true molar, and no calcar. The Common Vampire (_D. rufus_) is widely spread over the tropical and subtropical parts of Central and South America from Oaxaca to Southern Brazil and Chili. It is a comparatively small species, a little larger than the common Noctule, the head and body being about 3 inches in length, the forearm 2½, with a remarkably long and strong thumb; it is destitute of a tail, and has a peculiar physiognomy, well represented in Fig. 322. The body is covered with rather short fur of a reddish-brown colour, but varying in shade; the extremities of the hairs being sometimes ashy. The teeth are peculiar and admirably adapted for the purposes for which they are employed. The upper incisor is greatly enlarged, and of somewhat triangular shape (Fig. 323); the canine, although smaller than the incisor, is large and sharp; but the cheek-teeth are very small, with laterally compressed crowns rising but slightly above the level of the gum, their longitudinally disposed cutting-edges being continuous with the base of the canine and with each other. The lower incisors are small, bifid, and separated from the canine, with a space in front. The lower cheek-teeth are narrow, like those in the upper jaw, but the anterior tooth is slightly larger than the others, and separated by a small space from the canine. Behind the lower incisors the jaw is deeply hollowed out to receive the extremities of the large upper incisors. The exceedingly narrow œsophagus opens at right angles into the slender, intestine-like stomach, which almost immediately terminates on the right, without a distinct pylorus, in the duodenum, but on the left forms a greatly elongated fundus, bent and folded upon itself, appearing at first sight like part of the intestines. This cardiac extremity of the stomach is, for a short distance, to the left of the entrance of the œsophagus, still very narrow, but soon increases in size, till near its termination it attains a diameter quite three times that of the short pyloric portion. The length of this cardiac diverticulum of the stomach appears to vary from 2 to 6 inches, the size in each specimen probably depending on the amount of food obtained by the animal before it was captured.

_Diphylla._[639]—A small true molar in each jaw, and a rudimentary calcar. The single species _D. ecaudata_ inhabits Brazil, and appears to be much less abundant than _Desmodus rufus_, from which, in addition to the characters already mentioned, it is distinguished by its slightly smaller size, the absence of a groove in the front of the lower lip, the non-development of the interfemoral membrane in the centre, and the peculiar form of the lower incisors, which are much expanded in the direction of the jaws and pectinated, forming a semicircular row touching each other, the outer pair being wider than the inner ones, and having six notches, the inner pair having only three notches.

_Fossil Phyllostomatidæ._—Remains of _Vampyrus spectrum_, as well as of several species of _Phyllostoma_ or closely allied types, are found in the cavern deposits of Brazil. The mandible of a large Bat from the Upper Eocene Phosphorites of Central France, described as _Necromantis_, has been referred to this family—a determination which, if confirmed, will be of great interest from a distributional point of view.

_Bibliography of Chiroptera._—G. E. Dobson, _Catalogue of the
Chiroptera in the Collection of the British Museum_, 1878,
including descriptions of all the species of Bats then known;
subsequent papers by the same author in _Rep. Brit. Assoc._,
_Proc. Zool. Soc._, _Ann. Mag. Nat. Hist._, and _Bull. Soc.
Zool. de France_; by Peters in _Monatsb. Akad. Wiss. Berlin_;
by O. Thomas in _Ann. Mag. Nat. Hist._, _Proc. Zool. Soc._,
and _Ann. Mus. Genova_; and by J. Scully in _Ann. Mag. Nat.
Hist._ and _Journ. As. Soc. Bengal_; H. A. Robin, _Recherches
Anatomiques sur les Mammifères de l’Ordre des Chiroptères_,
Paris, 1881; W. T. Blanford, “Notes on Indian Chiroptera,”
_Journ. As. Soc. Bengal_, vol. lviii. (1888). See also papers
by Jentink, Bocage, and others.