The Chelydes. REPTILES. River Tortoises. 73 
and with the exception of the genns Chelodina we 
always observe two small barbels under the skin. The 
limbs are not much provided with scales, and the toes, 
which are deeply webbed, have in all but the genus 
Chelodina the fifth toe of the hind feet destitute of a 
claw. They are natives of ponds and rivers in warm 
climates ; eat flesh, feeding only in the water, and 
swimming with their whole shell under the surface. 
About thirty-four species have been described, which 
are nearly equally distributed in Africa, America, and 
Australia. 
Forming a sort of passage from the Terrapens to the 
Chelydes, we first come to notice the genus Sterno- 
TH.ERUS. In it the sternum or breastplate is mov- 
able, as well as in the Box tortoises ; but unlike that 
of the genus Cistudo, which has the sternum divided 
by two cross sutures, the central lobe being attached 
to the thorax by a bony suture, in this genus the 
breastplate is broad, and it is the front lobe only which 
is movable. It is rounded in front, and furnished on 
each side of its hinder edge with an internal bony pro- 
cess. The species are all natives of Africa. 
THE NATAL STERNOTHERE {Sternothmruscaslaneus) 
has been described and figured by Sir Andrew Smith 
in his “ Illustrations of the Zoology of South Africa. ” 
“ The first specimens,” he says, “ of this tortoise were 
discovered in rivers to the north of 25° south latitude ; 
and in situations only where the water was very deep. 
They were usually observed during the heat of the day 
lying upon rocks which projected above the surface of 
the water, and were so vigilant that it was almost im- 
possible to approach them within a moderate distance 
before they vanished. Many of them were struck by 
musket balls, yet no wounds which were thus inflicted 
ever appeared to impede their movements. At last, 
by means of hooks baited with flesh, we succeeded in 
obtaining a few specimens, though against such means 
they were also guarded ; for even where individuals 
existed in abundance, perhaps not one could be secured 
by four or five fishermen, after spending many hours 
in the pursuit.” This is the only species of the family 
that has the breastplate movable. In all the others 
it is solidly fixed. 
Amongst the species which are natives of America, 
one is very remarkable 
THE MATAMATA OR FIMBRIATED TORTOISE 
[Cheli/s matamata) is an animal of a very singular 
and unpleasing appearance, and is distinguished from 
all others by the extraordinary projection of its body 
out of the shell, so that when in a state of repose, el- 
even when suddenly wounded, it can only retract part 
of it within the shell. The neck is remarkably thick 
and flat, is seven and a half inches long and four and 
a half broad, and is fringed on each side and under- 
neath with a number of membranaceous appendages, 
disposed longitudinally, and alternately larger and 
smaller. The head is large and flat, rounded in front, 
and edged on the sides with a number of warty, mem- 
branaceous appendages similar to those of the neck. 
The muzzle is cylindrical, and is elongated in form of 
a tubular proboscis ten inches long, and pierced by the 
nostrils at the tip, where they are separated by a car- 
tilaginous division. The mouth is large and wide, 
VoL. II. 66 
and the jaws are simple and covered with soft lips. 
The shell is ovate, oblong, and the shields with which 
it is covered are elevated, acute, and form three keels. 
The breastplate is narrow, broader and rounded in 
front, and narrower and bifid behind. The colour of 
the carapace is a uniform deep-brown above, a little 
paler below. The total length of the animal is two 
feet three inches ; the shell being one foot three inches, 
and the neck seven inches long. It is a native of South 
America, and is known to the aboriginal inhabitants of 
the district of Cayenne, in which it used to occur plen- 
tifully, by the name of Matamata. Bruguidre was the 
first that gave an accurate description of this curious 
looking tortoise. According to him, it inhabits Guiana, 
in some parts of which it is very common, but is now 
become rare in the rivers of Cayenne, on account of its 
being so much in request as a highly prized article of 
food. It remains concealed during the day, and only 
sallies forth at night to feed. Its food is said by this 
author to consist of the herbs which grow upon the 
borders of the rivers and ponds in which it lives ; but 
this is denied by Martin, who affirms it to be carnivor- 
ous. “ It inhabits,” he says, “ fresh- water ponds and 
rivers, and conceals itself under the leaves of aquatic 
plants, with only the extremity of its nose, which is like 
a small proboscis, above the surface; in this position it 
awaits the approach of young birds, fishes, and small 
aquatic animals, which it seizes as they pass near it. 
It swims with rapidity, and darts eagerly on its prey.” 
About the latter end of last century, M. Gautier, 
governor of the Senegal Company of France, had 
several specimens collected by himself in Cayenne, one 
of which he kept alive in Paris for several months. 
During its captivity it was fed upon bread and herbs, 
which it ate readily, and before it died it laid five or 
six eggs. One of these, which was kept in a drawer, 
very unexpectedly excluded a young one. 
Several species of the family of Chelydes are, as we 
have mentioned above, natives of Australia, but we 
have not space for these. 
SOFT TURTLES or RIVER TORTOISES 
{Trionycidai). 
The species of this group of tortoises are compara- 
tively few in number, but they form a very natural 
family. Although inhabitants of the fresh water, 
they differ from the preceding families considerably 
in their conformation and structure, as well as in 
their habits. Like the Marine turtles, to be hereafter 
noticed, these River tortoises are compelled to live 
constantly in the water, but, unlike the Pond or Marsh 
tortoises, which we have already considered, and which 
sojourn in still water, as ponds, marshes, and slow run- 
ning muddy streams, these creatures inhabit large and 
rapid flowing rivers. They swim well and with great 
rapidity, and to answer this purpose their toes are 
deeply webbed to the very claws with broad flexible 
membranes. Their feet in fact, both fore and hinder, 
are changed into true fins, which are no longer fitted 
for progression on land, but are admirably adapted for 
propelling them through the water. Their neck is 
generally very long and protractile ; the head is narrow 
