38 
NATURAL HISTORY. 
[n. zool. gal. 
The lower shelves of this Case contain the double-headed snakes (^Am~ 
phisbcena), so called because both ends are nearb/ equally blunt, which 
has led to the idea that they could walk backwards and forwards with 
the same facility. 
Cases 25 — 26. The Batrachian Animals. 
The toads, frogs, and efts: the most remarkable are the tree frogs, 
which have the power of walking on polished surfaces, and of at- 
tachinsT themselves bv their feet to, and walking with their bodies sus- 
pended on the under side of the smoothest leaves ; they fix themselves 
directly they alight on any body, and, like many reptiles, they have the 
faculty of changing the colour of their skins, which often enables them 
to elude the vigilance of their enemies. The bull frogs of America; 
the homed toads of Brazil; the paradoxical frog from Surinam, the 
young or tadpole of which, when in its fish-like form, is larger than its 
parent, and has been described as a fish ; and Pqm of Brazil, which de¬ 
posits its eggs on the back of the male, who carries them a certain period, 
when the young are emilted from the cells; the siren of Carolina, 
W’hich looks like an eel with front legs ; the proteus of the dark sub¬ 
terraneous lakes of Southern Europe, which is of a pale pink colour, 
and blushes wben exposed to the light; of this there is a very accurate 
wax model, to exhibit its appearance wdien alive. 
The Tasle Cases. The Sea Eggs, Star-Fish and Encrinites. 
Tables 1 — 9. Sea Eggs. 
Tables 1—6. The globular sea eggs. The club-spined echinus 
(Case 3), wdiich has very large club-shaped spines; the tessellated 
echinus, which has short, broad, flat-topped spines like tessellated pave¬ 
ment. The spines easily fall off when the animal is dead, which makes 
specimens with spines on them rare in collections. 
Tables 7, 8. The Sea Pancaked, which are so depressed that there 
scarcely appears to be any room for their internal viscera; some of them 
are lobed or fingered on the margin, and others pierced with slits. 
Table 9. The Galerites, which are most abundant in a fossil state ; 
and some of the Sea Hearts, the species of which are continued into 
and occupy Case 10. 
Tables 11—18. The Star-Fish. 
Some have five and others many rays; some have the surface 
scattered with tubercles placed on the junction of a net-like skeleton, 
and others are formed of flat-topped pieces, like a tessellated pavement, 
each separate stem being fringed with an edge of minuter pieces; some 
of them bear on the top of each of the flat pieces a solid tubercle, 
which often falls off when the animal is dead. 
Tables 19—23. The Lizard-tailed Star-fish, 
So called because they often throw otf the end of their rays when they 
are handled or put into fresh water, as lizards do when they are caught 
and cannot escape. 
Table 23. The Gorgon’s Head, 
The arms of which are repeated branches, so as to end in in¬ 
numerable flexible filaments, by which the animal attaches itself to 
marine bodies, and strains its food from the surrounding water. 
