So 
TORTOISES AND TURTLES. 
resemblance to an alligator surmounted by a chelonian shell. It is one of two 
species belonging to a genus characterised by the eyes being directed upwards and 
outwards, so that their sockets are visible in a top view of the skull; by the tail 
being furnished with large horny shields on its lower surface; as well as by the 
absence of the supramarginal shields found on the carapace of Temminck’s 
snapper. The carapace, which may attain a length of at least 20 inches, is 
characterised by its rugose surface, bearing three well-marked tuberculated keels, 
which tend to become smoother with advancing age; while its vertebral shields 
are remarkable for their great width. The snout is short and pointed, with a very 
narrow space between the eyes; the skin is warty, and on the chin is developed 
into a pair of wattles or barbels. In the young the tail is as long or even longer 
than the shell, becoming relatively shorter in the adult; its upper surface having a 
crest of large compressed tubercles, while the shields on the lower surface have 
been already alluded to. As in the other members of the family, the colour is a 
uniform olive-brown. The alligator-terrapin inhabits the rivers of North America 
to the eastward of the Rocky Mountains, from Canada to Mexico, and is also found 
in Ecuador. A second living species {0. rossignonii), distinguished, among other 
features, by the presence of four wattles on the chin, is met with in Guatemala 
and Mexico. Nearly allied to this is a third and extinct species ( C. murchi- 
soni), from the Miocene rocks of Baden; and as we have already seen that the 
mud-terrapins, and probably also Maw’s terrapin, were represented-in the Tertiary 
strata of Europe, it is not improbable that the Eastern Hemisphere may have been 
the original home of the present group of families. 
Temminck’s Attaining considerably larger dimensions than the alligator- 
snapper. terrapin, Temminck’s snapper (Macroclemmys temmincki ) is dis¬ 
tinguished as a genus by the lateral position of the eyes, the sockets of which are 
invisible in a front view of the skull, as well as by the presence of three or four 
additional or supramarginal shields on the sides of the carapace, and by the under 
surface of the tail being covered with small scales. The triangular head is pro¬ 
portionately even larger than in the alligator-terrapin, and the carapace has three 
very strongly marked longitudinal ridges. In length, the shell may measure at 
least a couple of feet, the tail being somewhat shorter. This species inhabits 
North America from Western Texas to Florida, extending northwards to Missouri. 
Habits Since the alligator-terrapin and Temminck’s snapper appear to 
be very similar in their mode of life, their habits may be treated of 
collectively. Both these tortoises frequent alike the rivers and larger swamps of 
the United States, occurring in certain localities in enormous numbers, and most 
commonly in waters that have a muddy bottom, not even disdaining the most 
malodorous pools. As a rule, they lie in deep water, near the middle of the river 
or swamp, although at times they show themselves on the surface, where, with 
outstretched neck, they will float with the current. In populated districts the 
least sound is, however, sufficient to send them at once to the bottom, although in 
more remote regions they are less shy. At times they may be observed at 
considerable distances from the water, probably in search of food or of suitable 
spots to deposit their eggs. Temminck’s snapper well deserves its name, since, 
from the moment of its escape from the egg, it commences to snap and bite at 
