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 projoer. 



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.) 



