155 
N. ZOOL. GAL,] NATURAL HISTORY. 
delicacy, but it sometimes proves deleterious. Besides the 
preceding, there are specimens of the Globular Crabs (Leu- 
cosia ), Case 19; Sea Spiders (Leptopodia), Case 13, with 
their very long l$gs; Crested Crabs (Calappa), having the 
front part of the claws raised into a crest, and the hinder 
part of the shell projecting so as to cover the legs; and 
lastly, those Crabs which have the two hinder pairs of legs 
placed on their back (. Dorippe ), and the Death’s-head Crabs 
(Case 19), ( Dromia ). 
Long-tailed Crustacea, (Cases 20, 22,) as the Lobsters 
and Shrimps ; amongst which, those of the genus Hippa , 
(Case 20,) have the extremity of the tail simple. The 
Soldier or Hermit Crabs, (. Pagurus , Case 20,) live prin¬ 
cipally in the cavities of sponges, and also in the mouth of 
spiral shells, occasionally altering the texture of the latter, 
by some unknown process, to such a degree as to render 
them quite soft, and easily penetrable by a common pin. 
Amongst these is a fine specimen of Birgits latro , (Case 20,) 
said to live on the nuts of palm trees. Also specimens of 
the Sea Locust (Scyllarus), the Rock Lobsters ( Palinurus ), 
Case 21, the Plated Lobster ( Galathea ), Case 20, and the 
Crab Lobster ( Porcellana ), which, from the shortness of 
their tails, generally resemble crabs in appearance; the 
Scorpion Lobster ( Thalassina ), Case 21, which lives 
a great part of its life on land, and destroys the new made 
roads in India by the excavations it forms under them; 
Lobsters ( Astacus ), Case 21, one of the specimens exhibited 
was pale red, nearly of its present colour when alive; 
Shrimps ( Palcemon ), Case 22, varying greatly in size. 
The Stomatopodes or Sea Mantis, differ from the Deca - 
podes in the head being horny and separated from the 
thorax, and in having only three pairs of accessory jaws, 
seven pairs of feet, and the gills on the abdomen ; among 
these are different species of Squilla , the glass-like 
Alima and the Phyllosoina, which is scarcely thicker than 
a piece of paper, and nearly as transparent as glass ; they 
are found in the ocean near the equator. 
The remainder of the Crustacea (. Edriophtkalma ) have 
sessile eyes. 
The order of Arthrostraca (Case 21) have a free 
head, and their body composed of a series of similar 
rings, the first seven of which are each furnished with a 
