118 ZOOLOGY. 
simus, fig. 5) live upon the coast, digging holes several feet deep, where 
there is not too much sand to cause them to cave in, and some of the species. 
run so rapidly that a man can scarcely catch them. Ocypoda arenaria 
inhabits the coast of the United States and the Antilles, digging a hole three 
or four feet deep, just beyond the limit of the surf, whence it wanders in 
search of food. According to Say, they hybernate at some distance from 
the water, in a hole made for the purpose, the mouth of which they close. 
Gelasimus vocans, known on the United States coast under the name of 
fiddler, has one of the anterior feet of the male much larger than the other, 
the large one being indifferently upon the right or left aia 
Fom. 3 . Cancride, including the Portunide and Pilumnide of Leach, is 
oe to the Cyclométopes of Milne Edwards, and includes, under two 
sub-families, most of the forms known under the name of a The sub- 
families are: the Cancerine (Cancer, pl. 78, jigs. 1,2) and the Portu- 
nine (Thalamita, fig. 3), which includes a great number of species under 
various genera. They are found near the coasts a considerable number 
together, and are taken for food. They feed upon living or dead animal 
food, particularly upon decaying carcases. Some of them attain a large size, 
Pseudocarcinas gigas being ten inches or more in diameter. The Portunine 
correspond to Latreille’s swimming Brachyura, and are distinguishable from 
the Cancerinz by the posterior feet being flattened and adapted for swim- 
ming, as represented in figure 3. In Zwpa, the carapace is wider than long, 
and has nine tooth-like projections on each side before. The common 
edible crab of the Atlantic coast of the United States, has been described 
as Lupa hastata by Say, Jour. Acad. Nat. Sci. i. 65,1817. It is abundant 
in bays and inlets, feeds upon putrefying animal matter, and buries itself in 
the sand to the eyes and antenne. The shell is generally cast in the spring, 
when the animals are sought after under the name of soft crabs. 
fam. 4. Maride. This family includes the thorny and spider-crabs, many 
of which have long and slender feet. The epistoma, or region between the 
mouth and antennee, is large and square; the carapace is narrowed ante- 
riorly, so as to give it a triangular outline, whence Latreille’s names 
Triangulares and Oxyrhinchi. The front is narrow, and generally extended 
into a prominent.rostrum; the nervous system is more concentrated than 
in any of the other Crustacea, and on this account it may be considered the 
highest group among them. They are all marine, living at considerable 
depths; their motions are tardy, and they do not swim. As American 
examples, Leptopodia calcarata and Libinia comaliculata, Say, may be 
mentioned. There are two sub-families: MJatinw and Parthenopune. 
Class 4. Arachnida. 
This class includes the various articulate forms known as spiders, mites, 
and scorpions, the characters of which place them between the Crustacea 
and Insecta. In general, the head is not distinct from the thorax, but inti- 
mately connected with it, forming a large segment named the cephalothorax, 
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