186 CRUSTACEA. 



tremely spinous, and terminated anteriorly by a dentated point. These 

 Crustacea are peculiar to the Arctic Seas *. 



Our sixth section, that of the CRYPTOPODA f consists of Brachyura 

 remarkable for a vaulted projection of the posterior extremities of their 

 shell, under which their feet, the two anterior or the claws excepted, 

 can be completely retracted and concealed. The shell is nearly semi- 

 circular or triangular. The superior edge of the forceps is more or 

 less elevated and notched in the manner of a crest. In those species 

 where they are largest, they cover the anterior part of their body, 

 and hence the name of Coq de mer (Sea Cock), and Crabe honteux 

 (Bashful Crab), which have been given to some of them. One sub- 

 genus of this section, that of JEthra being closely allied by other cha- 

 racters with the Parthenopes of Fabricius, the first sub-genus of the 

 preceding section, it follows, in a natural order, 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. 



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

 shell are incised and dentated. 



One species, the Calappe migrane, Cancer granulatus, L. ; 

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

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

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

 equal 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 J. 



* Cancer inaja, L. ; Parfhenope maja, Fab.; Indchv.s maja, Id.; Lithodes arc- 

 tica, Leach, Malac. Brit., xxiv. See also the Maja camptschoisis, Tiles., Mem. 

 Acad. St. Petersb. 1812, V, VI. 



f Several of the Arcuata, such as the Hepati, Mursia;, Matutac, among the 

 swimmer*, luive a crested forceps, and seem to be naturally allied to the Crypto- 

 poda, so that this section should be placed higher in the scale. The same observa- 

 tion applies to the last one, or that of the Notopoda, for some of them approach the 

 Arcuata, and others the Orbiculata and the Trigona. 



J In thi-< division come the following species of Fabricius: C. tuberculata, 

 Herbst., XIII, 78; Iviii, 1 ? C. lophos, Herbst., XIII, 77; C. cristatus, Herbst.; 

 xl, 3; C. ,iiii,:ii!,,;ifiis, Herbst., xl, 2. The Gtiuju (t/H'ra, Pi.son and Marcgr., 

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

 is the Crabe des palttuviers of the colonists of Cayenne. The Cancer hepaticus of 

 Linnaeus is also a Calappa. 



