24 
NATURAL HISTORY. [UPPER FLOOR. 
skin, whence the older naturalists imagined the order of 
nature to be reversed in this animal, and that the frog be¬ 
came a tadpole, or as they called it, a fish,—an error long 
since exploded. The Tree Frogs ( Hyla ), have the ends 
of their toes dilated into a roundish disk, by which they 
climb. The Horned Frogs have the eyebrows extended 
into horns. 
In Case 3 are Toads ( Bufo ), some of them exceedingly 
large. The Bombinatores, or Earless Toads, differ from 
the others, merely by having the tympanum concealed 
under the skin. Some, as the Rhinellae, have their nose 
produced to a point ; and one ( Pipa ) is remarkable for 
its flattened shape, and for the manner in which the female 
carries her young in cavities, or little cells, on her back. 
The Salamanders (Salamandra), and Efts (Triton), follow 
the Toads: amongst them are the European species, ab¬ 
surdly supposed formerly, to be insensible to the action of 
fire; also several American species, as the Amphiuma, 
which is thought never to have any gills, though it pro¬ 
bably loses them at a very early age. At the end of these 
are placed the curious animals which Dr. Shaw called 
Dubious Amphibia, appearing to unite the amphibia with 
the fishes, and accordingly they have been placed in both 
classes by various authors. These animals retain their 
gills during the whole of their life, and are therefore capa¬ 
ble of living equally well on land or in water; .amongst 
these are the Axolotl of the Mexicans, which in all respects 
resembles the larva of the Common Eft; the Menobranchus 
from America, and the Proteus from the caverns of Car- 
niola, an animal which never voluntarily approaches the light 
of day, and whose very small eyes are so hidden by the 
skin, that it appears to be absolutely destitute of those organs. 
A wax model, from a living healthy specimen of this ani¬ 
mal, is placed near it, to show the form of its lungs when 
not contracted by immersion in spirits of wine. In this Case 
also is the Carolina Siren, first described by Ellis, which 
has only two short feet in front; and lastly the Caecilia, 
or blind Worm, whose eyes, always very small, and 
nearly concealed under the skin, are sometimes wholly 
wanting. 
Case 4 contains specimens of Crustacea, as Crabs, Lob¬ 
sters, and Woodlice, in spirits. 
