REPTILIA. 981 
are dilated at the base only. A single species only, ZZ verruculatus, is found 
in Europe, the rest are principally Asiatic and Australasian. 
The three next sections are known by the enlargement of the toes at the 
extremity only. In the first of these, Péyodactyla, the disk is emarginate 
in front, and provided beneath with imbricated lamellz arranged in a 
fan-shaped manner. One species, Uroplatus fimbriatus (pl. 88, fig. 5), 
inhabits Madagascar. The Phyllodactyla differ from the last in the 
absence of the inferior lamelle. One species, P. tuberculosus, is found in 
California. The Spheriodactyla have the toes dilated at the extremity into 
an entire disk, and are entirely without claws. The species inhabit the West 
Indies. 
The two remaining sections are without the usual dilatation of the toes. 
One of them, Gymnodactyla, has the simple toes unmargined and with 
transverse striz on the inferior face. The fifth toe of the hinder feet is 
versatile, answering the purpose of a thumb. Under this head is to be 
ranged the curious New Holland genus Phyllurus, with a tail flattened 
horizontally in the shape of a leaf. The concluding section, Stenodactyla, 
embraces but a single species, Stenodactylus guttatus, a native of Egypt. 
The simple cylindrical toes are indented along the edges, and are granu- 
lar on the inferior face. The fifth toe of the hind foot is very slightly-versa- 
tile. 
Fam. 7. Varanide. This family, interesting on account of the size of 
some of its species, which comes next to that of the crocodiles, is also 
important for the light which it throws upon the organization of certain 
fossil saurians. The body is greatly elongated, rounded, or cylindrical, and 
without dorsal crests. The tail is slightly compressed, and several times 
as long as the body. The body is provided with non-imbricated tubercles, 
which are set in the skin, rounded, except on the belly, and arranged in 
circular bands or rings. The belly is frequently provided with angular 
plates. The tongue is more like that of serpents than of the other 
saurians: it is protractile, playing in a sheath, and deeply split into two 
forks. which are capable of separation. The teeth, which are usually 
pointed and recurved, sometimes tubercular, are confined to the jaws, 
where they are inserted by their roots in a common groove. Some of the 
Varanide attain to a size which, among living saurians, is only exceeded by 
the crocodiles. None, as far as known, are arboreal. They inhabit sandy 
deserts, rocky situations, or the banks of rivers, where they feed upon insects, 
or even the smaller vertebrate animals. The Monitor of the Nile, Varanus 
niloticus, is said to perform essential service in devouring the eggs of the 
crocodile. 
Of the few species of this family, but one, Heloderma horridum, belongs to 
North America, where it is found in Mexico and California. None are Eu- 
ropean: Asia, Africa, and Oceania dividing the species pretty equally. 
We shall now briefly indicate a few of the more conspicuous fossil 
saurians, whose alliance is, to a greater or less extent, with the preceding 
families, especially with the Varanide. The genera Geosaurus and 
Mosasaurus were gigantic forms, each represented in the cretacean 
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