DECAPODA. 193 



It appears that from tlieir size, the form of their tail, and the 

 more solid consistence of their teguments, the Birgi are unable to 

 shelter themselves in shells. Thoy must retreat to holes, or fissures 

 in the rocks. 



The best known species. Cancer latro, L., Herbst. XXIV ; 

 Runiph., Mus., IV; Seba, Thes., Ill, xxi, 1, 2, according to the 

 Indians, feeds on cocoa-nuts, Avhich it obtains during its nocturnal 

 excursions for that purpose *. In the others, or the 



Pagurus, Fab., 



The last four feet are much shorter than the preceding ones, and 

 tlie fi)rceps are covered with granules. The tail is soft, long, cylin- 

 drical, narrowed near the extremity, and iias usually but a single row 

 of filiform oviperous appendages. Tlie thorax is ovoid or oblong. 



With the exception of some species domiciliated in sponges, Ser- 

 pulae and Alcyouii, they all inhabit univalve shells, whose aperture 

 they close with their anterior claws, and most frequently with one of 

 their fingers, which is usually larger than the other. It is asserted 

 that the female spawns twice or thrice in the year. 



Some species, C.enobita, Latr. ; distinguished from the others by 

 their projecting antennae, of wliich the mediate are nearly as long as 

 the external or lateral, and are furnished with elongated filaments, 

 whose thorax is ovoido-conical, narrow, elongated, strongly com- 

 pressed on the side, with the anterior cephalic portion shaped like 

 a heart, establish their domicile in terrestrial shells on rocks near 

 the sea, whence at the approach of danger, they roll down with 

 them f . 



The trvie Paguri — Pagurus, Latr., — on the contrary, have the me- 

 diate antennae curved, much shorter than the lateral ones, with the 

 two filaments short, the superior forming an elongated or subulated 

 cone ; the anterior division of the thorax is square, or forms a reversed 

 and curvilinear triangle. They inhabit marine shells. 



The Hermit, — Cancer Bernhardus, L., Herbst., XXII, Q\ Pa- 

 gurus streblonyx. Leach, Malac. Brit., XXVI, 1 — 4,^ — is of a 

 mean size. Its two claws are bristled with spines, with the 

 forceps almost in the shape of a heart, the right one being the 

 largest. The last joints of the ensuing feet are also spinous. It 

 is very common in European seas. A second but fossil species, 

 the Pagure de Faujas, — Desmar., Hist. Nat. des Crust. Foss., 

 XI, 2, — is closely allied to it. 



A third species, the Pagurus angulatus, Risso, Crust, de Nice, 

 I, 8; Desmar., Consider., XXX, 1, is remarkable for its forceps, 



* Pagurus lutiraudu, Cuv. RegH., Aiiira., IV, xii, 2; Desmar., Consider, p. 

 180, from the Isle of France. Very curious facts relating to the anatomy of the 

 preceding species have been published by M. Geoflroy Saint-Hilaire, from which 

 however we do not draw similar conclusion.-. 



-f- Pagurus clypeutus, Fab.; Herbit., -xii, 2. 

 VOL. Ilf. O 



