378 BAT where there is not even a ray of light, and are intended, by increasing the delicacy of the sense of smell, to act as substitutes for eyes in situations where vision is impossible. Bats have such an extraordinary exaltation of the sense of touch, that Spallanzani was led into the belief that they had a sixth sense; his experiments showed that they could fly with perfect accuracy in the dark, avoiding every j obstacle, even after the eyes were put out and the ears and nose completely stopped up. But Cuvier discovered that this exquisite sense of touch resides in the flying membrane. This membrane arises from the skin of the flanks, and consists of an abdominal and a dorsal leaflet, united into an exceedingly thin and delicate network ; it includes not only the arms and hands, but the hinder extremities, being prolonged more or less, according to the genera, between the legs, and spread the length of the tail, forming a sensitive surface entirely disproportionate to the size of the body ; to increase its sensitiveness, it is entirely or nearly destitute of hair. The bat, therefore, is made acquainted with the distance of bodies by the different modifications impressed upon this membrane by the impulse of the air. The only 'peculiarity in the nervous system is the large size of the spinal cord in the lower cer- vical and dorsal region, from which arise the nerves of sensation distributed to the wings. In the nycteru, an African genus, the skin adheres to the body only at certain points, and by a loose cellular membrane, and is capable of being inflated with air by a communication with the large cheek pouches; this inflation may be carried to such an extent that the ani- mal resembles a balloon with head, wings, and feet. The mouth of the bat is uncommonly large, affording great facilities for the capture at (Vamplrus spectrum). of insects on the wing. In the genus vampi- rus or pkyllostoma, peculiar to America, the tongue is provided at its extremity with a cir- cular row of wart-like elevations, forming a complete suctorial disk ; by means of this these animals are enabled to suck the juice of fruits and the blood of animals. By mistake this faculty has been attributed to some of the large species of the pteropus of Asia, and hence have arisen the fearful stories of the fabulous vam- pire, which destroyed people at night by suck- ing their blood, fanning their victims into un- consciousness by the flapping of their wings. The vampire bat is a large South American species, of the genus vampirus, whose natu- ral food is insects, but which, if pressed by hunger, will suck the blood of poultry, cattle, and even of man ; the blood is obtained en- tirely by suction from the capillary vessels, and not through any wounds made by the teeth ; the stories told by travellers are much exaggerated, as the animal is harmless and not at all feared by the natives. The insectivorous bats have the simple stomach and short intes- tines of the carnivora ; while the frugivorous Flying Fox or Roussette (Pteropus rubricollis). species have a complicated stomach and a long alimentary canal. Bats are natives of all the temperate and tropical regions of the globe ; those of North America belong chiefly to the vespertilionidce. The large East India species, the roussettes, of the genus pteropw, are exten- sively used as food. The fur of bats is generally exceedingly fine and soft. Bats fly to a consider- able height and with great rapidity ; they are nocturnal in their habits, avoiding the light and noise of day ; in the warm summer evenings they sally forth in search of prey, and them- selves fall easy victims to the owls and birds of night and to any snare that may be set for them ; they pass the winter, and indeed the greater part of the year, in a state of torpid- ity. The cheiroptera are intermediate between the quadrumana and the true insectivora. The galeopithecus, or cat-monkey, of the Indian archipelago, presents many characters of the
Page:The American Cyclopædia (1879) Volume II.djvu/398
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