50 CRUSTACEA. 



the Cryptopoda should be placed between the Orbiculata and the 

 Trigona. 



Calappa, Fabr. 



An extremely convex shell; the forceps triangular, strongly com- 

 pressed, dentated superiorly like a crest, and perpendicularly cover- 

 ing the anterior part of the body, during the contraction of the feet. 

 The third joint of the external foot-jaws is terminated like a hook, 

 and the superior extremity of the buccal cavity is contracted and 

 divided longitudinally into two cells by a septum. 



n most of them, the two posterior and lateral dilatations of the 

 shell are incised and dentated. 



One species, the Calappe migrane, — Cancer granulatus, L.j 

 Calappa granulata^ Fab.; Herbst., XIII, 75, 76, vulgarly styled 

 Coq de mer and Crabe honteux, is found in the Mediterranean, 

 The shell is reddish and marked with two deep sulci, and une- 

 qual tubercles of a carmine red. That portion of the lateral 

 margin which precedes the posterior dilatations, is at first 

 nearly entire, and terminates by four very short teeth, the two 

 first being most strongly marked; those of the edges of the 

 dilatations are large, and six in number, two on the posterior 

 margin, and the others lateral. There are two others on the 

 front. The forceps are also furnished with red tubercles, and 

 their crest is formed by seven teeth, the superior of which are 

 acute(l). 



The others, such as the C. voute — Cancer calappa, L.j Calappa 

 fomicata, Fab.; Herbst., XII, 73, 74, have the marginal dila- 

 tations of the shell entire. This species inhabits the seas in the 

 vicinity of Australia and the Moluccas. 



^THRA, Leach. 



The iEthrae diff'er from the Calappse in their very flat shell, in their 

 forceps, which are not raised perpendicularly, and which do not 

 overshadow the forepart of their body, and in the almost square 

 form of the third joint of the external foot-jaws. 



(1) In this division come the following species of Fabricius: C. iuberculata, 

 Herbst., XlII, 78; Iviii, 1?— C. lophos, Herbst., Xlll, 77;— C. cristaius, Herbst., 

 xl, 3; — C. marmoratus, Herbst., xl, 2 — The Guaja apara, Pison and Marcgr., 

 should probably be referred to this species, and according to the citation ofBarere 

 is the Crabe des paletuviern of the colonists of Cayenne. The Cancer Jiepaticus 

 of Linnseus is also a Calappa. 



