FOUR NEW SYMMETRICAL HERMIT CRABS (PAGURIDS) 

 FROM THE WEST INDIA REGION. 



B}^ James E. Benedict, 



Assistant Curator, Division of Marine Invertebrates. 



The specimens described in this paper were all dredged by the LT. S. 

 Fish Commission steamer Albatross in 1885, and all belong to the 

 West India region, with the possible exception of Mki'tajxtgurns ylUi^ 

 which was taken in 107 fathoms off North Carolina, the extreme 

 northern limit of the region. 



The symmetrical Pagurids are regarded as approximating the ma- 

 cruran type more closely than the other members of the family. The 

 relationships of PylocJieles and MixtojMgiii'us and other forms with 

 calcified dorsal abdominal plates are discussed by A. Milne-Edwards 

 and Boiivier in the Blal'e Pagurids.^ 



Cancellus Edwards is a well characterized genus. The door or cover 

 to its dwelling is formed by the facets of the chelipeds and of the first 

 pair of ambulator}^ legs, which are much modified for this purpose. 

 The abdomen in the three species before me is spherical, as is also 

 that of CanceUus typus Edwards and of Cancellus tanneri Faxon; the 

 only exception to this structure is furnished b}^ the Cancelhis canali- 

 culatus (Herbst), which is figured with a conventional abdomen. The 

 abdomen in this genus seems to be even more readily separated from 

 the thorax than in other genera, and this separation had not unlikel}^ 

 taken place in Herbst's specimen and the conventional form may have 

 been added to the figure for the sake of completeness. A notalile 

 case of the substitution of a wrong part occurs also in Herbst's famous 

 work,^ where his Cancer megistos is shown with the abdomen of a 

 macruran. 



The Mixtojxigurus di^savihedi shows an interesting variation from the 

 type species of the genus in having a decidedly unsymmetrical telson. 



i Mem. Mus. Comp. Zool. XIV, No. 3. ^ pj^te lxi, fig. 1. 



Proceedings U.S. National Museum, Vol. XXIIl— No. 1236 . 



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