DECAPODA. 169 



widened form of their shell, and the shortness of their lateral antennae, 

 approaching the Mursise and Calappe in their compressed hands, the 

 upper edge of which resembles a crest ; but the third joint of their 

 external foot-jaws form an elongated, narrow, and pointed triangle, 

 without any apparent eroargination, a character also observed in the 

 Matutse and Leucosiae. 



The species * which served as the type of this division was 

 confounded by Fabricius with the Calapp. It it as large as an 

 ordinary Pagarus. The shell is yellowish, dotted with red, and 

 the margins finely and unequally crenulated. The eyes are 

 small and approximated, and the feet are traversed by red 

 bands. Although the tail of the male has but five complete seg- 

 ments, the traces of two others may still be discovered on the 

 sides. This species is common at the Antilles. 



In our third section, or that of the Quadrilatera, the shell is 

 nearly square or heart-shaped, the front generally prolonged, in- 

 flected or much inclined, and forming a sort of clypeus. There 

 are seven segments, distinctly marked across their whole breadth, 

 in the tail of both sexes. The antennae are usually very short. 

 The eyes of most of them are fixed on long or stout pedicles. 

 Several live habitually on land, inhabiting holes excavated by them- 

 selves ; others frequent fresh- water streams. They move with great 

 swiftness f. 



A first division will comprise those in which the fourth joint of 

 the external foot-jaws is inserted at the superior internal extremity of 

 the preceding one, either in a short, truncated projection, or in a si- 

 nus of the inner margin. They approach nearest to the Crabs proper. 



The shell of some is nearly square, or a trapezium, but not trans- 

 verse, or almost in the form of a truncated heart. The ocular pedi- 

 cles are short, and inserted either near the lateral and anterior angles 

 of the shell, or more internally, but always at a considerable distance 

 from the middle of the front. Here comes the 



Eriphia, Lat. 



Where the lateral antennae are inserted between the ocular cavi- 

 ties and the median antennae ; the nearly cordiform shell is truncated 

 posteriorly, and the eyes are removed from its anterior angles. 



The coast of France furnishes a species — Cancer spinifrons. 

 Fab.; Herbst., XI, 65 ; Desmar., Consider., XIV, 1, which is 

 the Pagurus of Aldrovandus. The sides of its shell are fur- 

 nished with five teeth, the second and third bifid. The fi'ont 

 and claws are spiny ; the fingers black. 



* Hepatus fasciatus, Latr. ; Desmar., Consider., IX, 2 ; — Calappa angustata 

 Fabr. ; Cancer princeps, Bosc. ; Herbst., xxxvii, 2. See also his Cancer armadillus, 

 VI, 42, 43. 



t I consider them, with respect to their habits and some of the characters of 

 their organization, as being the furthest removed from the other Dccapoda ; they 

 should be placed at one of the extremities of that order. 



