154 
CLASS CRUSTACEA. 
their hands being compressed, and terminated above in the 
manner of a ridge : but the third articulation of their external 
jaw-feet is in the form of an elongated triangle, narrow, and 
pointed, without apparent emargination, a character also ob- 
served in Matuta and Leucosia. The type on which this sec- 
tion is founded is Hepatus fasciatus (Latr.), which Fabricius 
has confounded with Calappa. 
A third section, Quadrilatera, has the testa almost 
square, or formed like a heart, with the front generally pro- 
longed, inflected, or very much inclined, and forming a sort of 
hood. The tail of the two sexes is of seven segments distinct 
in their whole breadth ; the antennae are generally very short; 
the eyes of the majority are supported on long or thick pedi- 
cles. Many live habitually on land, in holes which they 
excavate ; others frequent fresh water. Their course is very 
rapid. 
A first division will comprehend those in which the fourth 
articulation of the external jaw-feet is inserted at the internal 
upper extremity of the preceding articulation, either on a 
short and truncated projection, or in a sinus of the internal 
edge. These are they which approach the nearest to the 
crabs proper. 
Some have the test sometimes square or trapezoid, but not 
transverse, sometimes in the form of a truncated heart ; the 
ocular pedicles are short, and inserted either near the lateral 
and anterior angles of the test, or more interior, but always at 
a sufficiently great distance from the middle of the front. 
Here come 
Eriphia, Latr ., 
Which have the lateral antennae inserted between the ocular 
cavities and the medial antennae ; the test is almost always 
heart-formed, truncated posteriorly, and the eyes are remote 
from its anterior angles. ( Cancer Spinifrons , Fab.) 
