PHYLLOSTOMA TIDAZ 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 Demodus 

 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 Aoav 

 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 

 Xoctule, the head and body being about 

 3 inches in length, the forearm 2 -A, with 

 a remarkably long and strong thumb ; 

 it is destitute of a tail, and has a 

 peculiar physiognomv, well represented Pro. 322.— Head of Vampire Bat 

 in Fig. 322. The body is covered with ('>«<««'<« mfus). 



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. Xntacsch. Brasil, vol. ii. p. 231 (1826). 



