192 



CRUSTACEA. 



laminiform, emarginated at the end and covering the ensuing joints. 

 The shell is nearly ovoid, convex, and truncated at both ends. 



The last joint of the second feet and of the two following pairs is 

 triangular, but approaching, in the latter at least, to the form of a 

 rivscent; the two last of the fourth pair are turned up, and laid on 

 the two preceding ones; the first segment of the tail is marked with 

 two impressed and transverse lines *. 



REMIPES, Lat. 



The two anterior feet elongated, the last joint conical, compressed, 

 and hairy ; the four antennae closely approximated, very short, and 

 nearly of an equal length, the intermediate ones terminated by two 

 filaments ; ocular pedicles extremely short and cylindrical ; external 

 foot-jaws in the form of small claws, thinned and arcuated at the end, 

 and terminated by a stout hook. The shell is shaped like that of the 

 Hippre. 



The last joint of the second and third feet forms a triangular blade, 

 with an emargination in its external side; the same joint of the 

 fourth is triangular, narrow, and elongated. As in the Hippse, the 

 first caudal segment presents two impressed and transverse lines. 



Two species are known ; one from the Australian Sea f, and 

 the other from the Antilles, and the coast of Brazil. 



There (the Pagurii, Latr.), the teguments are somewhat crus- 

 taceous, and the tail is most commonly soft, contorted, and in the 

 form of a sac. The two anterior feet terminated in a didactyle hand, 

 the four following ones in a point, and the four posterior, which are 

 shorter, in a sort of forceps or little didactyle hand. The first joint 

 of the peduncle of the lateral antennae presents a pointed or spiniform 

 appendage or projection. 



These Crustacea, termed Carcinion by the Greeks, and Cancelli 

 by the Latins, usually inhabit empty univalve shells. Their tail, that 

 of the Birgi excepted, presents but three false feet, (in the females 

 only), situated on one of the sides, each of which is divided into two 

 filiform and hairy branches. The three last segments are suddenly 

 narrowed. In some of them, such as the 



BIRGUS, Leach) 



The tail is tolerably solid, suborbicular, and is furnished beneath 

 with two rows of laminiform appendages. The fourth feet are but a 

 little smaller than the two preceding ones ; the two last are folded and 

 concealed, their extremities being received into a depression at the 

 bottom of the thorax ; the fingers at the extremity, as well as those 

 of the penultimate pair, are hairy or spinous. The claws excepted, 

 all the feet are visibly separated at their origin. The thorax has 

 the figure of a reversed heart, and is pointed anteriorly. 



* Hippu adacfyla, Fab. ; H. emeritus. Id. ; Cancer emeritus, L. ; Emerita, Gro- 

 nov., Zoop., xvii, 8, 9; Herbst., xxii, 3 ; Desmar., Consider., xxix, 2, in the seas 

 of both Indies. 



f Remipes testudinarius, Latr. ; Desmar., Consul., xxix, 1 ; Cuv., Rgne Animal, 

 IV, xii, 2. 



