ocodile
of the Nile. The monitor of New Holland is specifically distinct from
the Indian species; these latter, again, from the African, and all from
their congeners in the new world. So in regard to snakes; we find the
boa of America represented by the python, a different though nearly
allied genus in India. America is the country of the rattlesnake;
Africa, of the cerastes; and Asia, of the hooded snake, or cobra di
capello. The amphibious genera Siren and Menopoma belong to North
America, possessing both lungs and gills, and respiring at pleasure
either air or water. The only analogous animal of the old world is the
_Proteus anguinus_ of the lakes of Lower Carniola, and the grotto of
Adelsberg between Trieste and Vienna.[906]

There is a legend that St. Patrick expelled all reptiles from Ireland;
and certain it is that none of the three species of snakes common in
England, nor the toad, have been observed there by naturalists. They
have our common frog, and our water-newt, and according to Ray (Quad.
264.), the green lizard (_Lacerta viridis_).

_Migrations of the larger reptiles._--The range of the large reptiles
is, in general, quite as limited as that of some orders of the
terrestrial mammalia. The great saurians sometimes cross a considerable
tract in order to pass from one river to another; but their motions by
land are generally slower than those of quadrupeds. By water, however,
they may transport themselves to distant situations more easily. The
larger alligator of the Ganges sometimes descends beyond the brackish
water of the delta into the sea; and in such cases it might chance to be
drifted away by a current, and survive till it reached a shore at some
distance; but such casualties are probably very rare.

Turtles migrate in large droves from one part of the ocean to another
during the ovipositing season; and they find their way annually to the
island of Ascension, from which the nearest land is about 800 miles
distant. Dr. Fleming mentions, that an individual of the hawk's bill
turtle (_Chelonia imbricata_), so common in the American seas, has been
taken at Papa Stour, one of the West Zetland Islands;[907] and,
according to Sibbald, "the same animal came into Orkney." Another was
taken, in 1774, in the Severn, according to Turton. Two instances, also,
of the occurrence of the leathern tortoise (_C. coriacea_), on the coast
of Cornwall, in 1756, are mentioned by Borlase. These animals of more
southern s