426 
VERTEBRATA. 
v/nP' I ft//'/ 
HEAD OF HELIOPHOBIDS. 
swim well. The species are not only exceedingly numerous, but very generally distributed in all 
parts of the world ; some are even indigenous to Australia. Under this head we shall first notice 
the tribe of Rat-Moles, and then the Muriens, of which the principal types are the Field-mice and 
common Hats and Mice. • 
THE RAT-MOLES. 
This tribe are all burrowers, have a large head, the 
tail short or altogether wantiug, and the eyes very small. 
There are several genera, as Bathyergns, Georychus, 
JRhizomys, Siphneus, Sjyalax, and Reliophobivs. 
Genus HELIOPHOBITJS : Heliophobius.—Oi this 
there is a single species, H. argenteus, which is the only 
one of the Rodentia which has five pairs of molars in each 
jaw. It is little known beyond its appearance ; it is of a 
silver-gray color, and has a head and feet not easily de- 
scribed, and of which we therefore present engravings. 
Genus BATHYERC4US : Bathyergus.— These animals, 
belonging to Africa, have no external ears; they have 
extremely small eyes, a short tail, and a squat body ; 
they burrow and form galleries, like the moles, in sandy 
wastes, generally near the sea. These are the proper 
Hat-moles. There are several species, as follows : 
The Coast Rat, or Cape Mole, the Great CajM Mole 
of BufFon, the Zand Moll of the Dutch, and Kauw- 
Ilouha of the Hottentots, B. maritimus, is nearly the 
size of a rabbit, being thirteen inches long, and its tail a 
little more than one inch. It perforates the earth with 
its long, horizontal galleries in such a manner that 
persons often break into them and sink up to their 
knees, and rendering it exceedingly dangerous to ride 
among them. It lives on roots and bulbs, and is found 
in the region of the Cape of Good Hope, especially in 
the sand-flats near the sea. It is of a reddish-gray color. 
The Hottentot Bathyergus is of a brownish-gray, 
and is half the size of the preceding ; this also is found 
near the Cape. Two other undescribed species are men- 
tioned by naturalists : one is called B. Buffonii ; the 
other is yet unnamed. 
Genus GEORYCHUS : Georychus.—Oi this there is 
a single species, the G. Cajnnsis ; this is five inches long, 
with a tail two-thirds of an inch. It lives in burrows, 
and generally resembles the Bathyergus. It is found in 
South Africa. 
There are several species of field-mice, arranged under 
this genus by some authors, which we shall notice under the head of Lemmings. 
Genus RHIZOMYS : Rhizomys. — These animals have a long body, small eyes, and short 
tails, and resemble the rat-moles. A single species only is well known, the Bamboo-Rat, 
R. Sumatrensis, the body of which is thirteen or fourteen inches long, and the tail five ; 
the general color is a light yellowish-gray; it has been erroneously referred to Sumatra and 
Java; its true habitat is in the dense and almost impenetrable bamboo thickets of Malacca. 
It feeds on the young roots of that plant, and on various fruits. It lives in burrows, from which 
it only issues at night. This animal is described by Temminck under the name of the Deccan 
JVyctoclejJes^ and is probably the same as the R. Chinensis of Gray. The Mus talpinus, of Pallas, 
PACE OF HELIOPHOEIUS. 
FEET OF HELIOPHOBIUS. 
