Mr. Gosse observed the habits of this and the preceding Bat in Jamaica, and describes them as exhibiting a special partiality for the fruit of the Achras sapota, called in Jamaica the naseberry, a preference already observed by Mr. A. Ricord in the case of the Spectacled Stenoderm. Mr. Gosse says:—“About a quarter of an hour after the sun has disappeared, and while the western horizon is yet glowing with those effulgent peak-like clouds which only a tropical sunset displays, we discover, by attentively watching the tree, the Bats begin to visit it. First one comes, takes a rapid flight around the tree, darts once or twice through the dense foliage, and winging away is lost in the light of the sky. Another and another comes immediately, and performs the same evolutions; and as the glory of the west fades away to a warm ruddy brown, like the blush of a mulatto girl, many dusky forms are discerned flitting round and round. By carefully following the flight of an individual with the eye, we perceive that now and then he alights for a moment on some object at the extremity of a bunch of leaves; but no sooner has the eye rested on the spot than the sooty wings are again spread, and he is pursuing his giddy course with his fellows. The object of his attention is a ripe naseberry, nestled in the midst of that rosette of leaves. Occasionally the weight of the suspended Bat dislodges the ripe fruit, and it falls to the ground, splitting with the shock. On picking it up, we see that it has been just bitten, not gnawed, as by the rodent incisors of a Mouse, but nibbled in a ragged manner. Though the Vampires often eat the fruit on the tree in this manner, detaching minute morsels, and again and again returning for more, it appears that not seldom they succeed in tearing out a large piece, which they carry away; for fragments of naseberry of considerable size, partly eaten by a Bat, are frequently found at the distance of half a mile from the nearest naseberry tree, dropped on the high road.” Mr. Gosse adds that this Bat also feeds on the rose-apple, and Mr. Osborn describes it as consuming all the same fruits as the preceding species.[247]
THE DESMODUS.[248]
The Desmodonts are in some respects among the most remarkable forms of Bats; indeed, their characters are so peculiar that it may be a question whether they ought not to form a distinct family in the order Chiroptera. By some zoologists, indeed, this course has been adopted, but as they agree with the Phyllostomidæ in the presence of nasal appendages, and in the possession of three phalanges in the middle finger, we have preferred to leave them in that family, at the same time indicating their striking divergences from all its other members.
The dentition in these Bats is most singular, and as we shall see, its peculiarities are so associated with the exceptional habits of the animal, as to have far greater weight in the question of classification than we have accorded to the dental characters in other families. In fact these peculiarities, in combination with certain points of internal anatomy, are so remarkable that Professor Huxley has suggested the formation for the Desmodonts of a distinct group (Hæmatophilina) of the Microchiroptera, which he apparently regards as equivalent in classificational value to all the rest of the sub-order taken together.
The remarkable conformation of the teeth will be easily seen by reference to the [annexed figure]. The upper incisor teeth, four[249] in number in the young animal, become reduced to two in the adult, but these are of enormous size, prominent, triangular, and very sharp. The lower incisors, on the contrary, are small and have a two-lobed crown. The canines of the upper jaw are nearly of the same form as the incisors, but rather smaller; those of the lower jaw present no remarkable peculiarity. The molar series of teeth, however, are most peculiar—there are two in the upper and three in the lower jaw, but the whole of them are small, compressed, sharp-edged, and furnished with only a single root, thus presenting the characters of premolars, as which, indeed, they are regarded by some writers. If this view of their nature be correct the Desmodonts have no true molars.
SKULL OF DESMODUS.
In general characters these Bats approach the Stenoderms. The tail is entirely deficient; the interfemoral membrane forms a mere border to the legs; the ears are of moderate size and furnished with a small tragus; and the nasal appendage consists only of the part analogous to the horseshoe in other genera, the upper leaf being absent. The thumb is very long and strong. The only species of the genus Desmodus (D. rufus) measures about four inches in length, and some fifteen or sixteen inches in expanse of wing. The fur varies considerably in colour, but generally shows various tints of brown, from a reddish-brown, as in the specimen originally described by Prince Maximilian, through a plain brown, to ashy-brown and mouse-colour, variations which have induced zoologists to describe several distinct species, now, however, generally regarded as identical. This species in its various forms seems to be very generally distributed in all the warmer parts of South America, from Chili to Guiana. As already stated, it appears to be the only species that has been detected in the act of blood-sucking; and by some of the most recent authorities it and its near ally, Diphylla ecaudata, are believed to be the only South American Bats which are really guilty of that atrocity.
Dr. Hensel, who has discussed this matter at some length, in connection with his observations on the Bats of Brazil, remarks that the teeth of most of the Phyllostomidæ are like those of the true Carnivora, and the wounds inflicted by them, as may easily be observed by the captor of one of them, are of the same kind as those produced by the teeth of a small Carnivore. In the latter, as he says, there is no loss of substance; the bite consists usually of four punctures, where the canine teeth have pierced the skin, and severe bleeding occurs only when these teeth have penetrated to some depth, and injured one or more of the larger vessels.
