PHYLLOSTOMATIDA 677 
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 gener- 
ally 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.1—No true molar, and no calcar. The Common 
Vampire (D. rufus) is widely spread over the tropical and sub- 
tropical 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 24, with 
a remarkably long and strong thumb; 
it is destitute of a tail, and has a 
peculiar physiognomy, well represented — Fie. 322.—Head of Vampire Bat 
in Fig. 322. The body is covered with sc imiabtsiats 
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 
1 Wied, Beitr. Natgesch. Brasil, vol. ii. p. 231 (1826). 
