THE STRAW-COLOURED RAT 
31L 
■except the last joint, in the interfemoral membrane, which is supported by long heel-spurs, beyond 
which there are membranous lobes ; and the thumbs are free and clawed, and, like the soles of the feet, 
furnished with curious adhesive discs. The toes consist of only two phalanges each, as in the genus 
Phyllorhina. The genus was described by MM. Lichtenstein and Peters 
under the name of Hyonycteris (Pig Bat), in allusion to the elongated 
and truncated form of the muzzle, which has somewhat of a Pig-like 
aspect. 
The singular adhesive organs mentioned above as occurring on the 
thumbs and feet of this Bat, are described in considerable detail by Mr. 
Dobson in the “ Proceedings of the Zoological Society.” He remarks that 
they constitute the only known instance of the possession by Mammals 
of prehensile organs at all resembling the sucking-discs of the Cephalo- 
podous mollusca. “ On the inferior surface of the thumb,” he says, “ from 
the base of the first phalanx, .... corresponding to the position 
of the ball of the thumb in other Bats, arises, by a short peduncle, a hollow suctorial disc about one- 
tenth of an inch in diameter. On the sole of the foot a similar but considerably smaller disc is placed, 
not in the same relative position, however, as in the thumb ; for it covers the metatarsal bones, not 
the bases of the first phalanges of the toes.” According to a Spanish writer, Senor Jimenez de la 
Espada, these discs were used by the animal to fasten itself to the fingers as it tried to bite, producing 
the same feeling as a key or thimble when applied to the tongue after sucking out the air ; and it is 
added, “the muscular arrangement is such as to allow the animal to vary the diameter of the organ; 
and by their means the animals attached themselves to the sides of the box in which they are kept, 
although, when sleeping, they suspended themselves by the claws like other Bats.” Mr. Dobson, 
however, by careful examination of the structure of the discs, convinced himself that the Spanish 
zoologist was mistaken in ascribing any muscular arrangements to these curious organs, which consist 
exclusively of an unusual development of the skin and subcutaneous tissue, amongst which a radiating 
cartilaginous structure probably gave rise to the notion of a special muscular apparatus. Mr. 
Dobson indicates further that the discs of the feet are supplemented by several small projections 
from the hinder border of the lieel-spur, which are known to occur in no other species of Bat, and 
he regards the whole of these peculiarities as indicating that the animal is specially adapted for 
climbing, like the New Zealand Bat ( Mystacina tuber culata ), and that in all probability both these 
species are in the habit of capturing the insects on which they feed while crawling over the branches 
of trees.* 
The Brown Pig Bat ( Thyroptera tricolor) is an inhabitant of South and Central America. Its 
head and body are rather more than an inch and a half long, and the tail about an inch and a quarter. 
The fur is of a cinnamon-brown colour, paler beneath, and the wings dusky brown, t 
THE STRAW-COLOURED BAT + 
In this curious little Bat, as in Fiiripterus and Miniopterus , which with it form the links of connec- 
tion between the two families of simple-nosed Insectivorous Bats, the crown of the head is also much 
elevated and separated from the muzzle by a strong depression. The nostrils are placed quite at the tip 
of the nose, and close to the upper lip (see figure, p. 312), the chin has a semicircular double row of warts, 
the ears are large, broad, somewhat pointed at the tip, which is turned outwards, so as to make the outer 
margin appear excavated, whilst below it sweeps round upon the side of the face as a free lobe, and the 
tragus, which is short, broad, and fleshy, rises from the end of a short stalk projecting horizontally 
from the inside of the opening of the ear. The wings are of moderate length, and rather broad, and 
are attached to the ankle in a most singular manner. Their point of attachment is not, as usual in 
Bats, on the outside, but on the inside of the ankle, so that a narrow strip of membrane has to cross 
* Mr. Dobson’s paper above referred to (“Proceedings of the Zoological Society,” 1876, p. 526) contains some interesting- 
particulars as to the occurrence of adhesive organs in Bats and other Mammals. 
f A second species, Thyroptera albiventer , has been described by Mr. Tomes from the vicinity of the Rio Napo, near 
Quito. It is rather larger than the preceding, and of a reddish-brown colour above, with the lower parts pure white. 
$. Natalus str amine us. 9 
FOOT AND THUMB OF THE BROWN 
PIG BAT, ENLARGED. 
(From the Proceedings of the Zoological 
Society.) 
