s 



245 



Subfam. Pinnotherinae. 



This group contains the most typical representatives and is immediately recognizable by 

 the shape of the external maxillipeds, besides by the carapace being nearly always of a parch- 

 ment-like consistence and subcircular or indistinctly angular, but without sharpened lateral 

 margins, which never present teeth or notches. 



Key to the genera : 



1. Palp of ext. maxillipeds two-jointed only, the dactylus being 



absent 2 



Palp of ext. maxillipeds three-jointed, the dactylus being 

 generally inserted at the inner side of the propodus . 4 



2. Terminal joint of palp of ext. maxillipeds widening distally. 3 

 Terminal joint of palp of ext. maxillipeds not widening 



distally Ostracotheres H. Milne-Edwards 



3. Dactjli of walking legs, except those of last pair, deeply 



bifurcate Dissodactylus S. J. Smith 



Dactyli of walking legs simple, about as long as propodites. 



Orbits ventral in position. Carapace well calcified . . Cryptophrys Rathbun 



4. Lateral margins of carapace thickened, upturned ... 5 

 Lateral margins of carapace not upturned 6 



5. Middle of carapace with a prominent tubercle, shaped like 



a mushroom and reniform Xanthasia White 



Middle of carapace with a longitudinal ridge .... Diirckheimia (Ruppell) de Man 

 6' Propodus of ext. maxillipeds longer than merus. Carapace 



well calcified Scleroplax Rathbun. 



Propodus of ext. maxillipeds much shorter than merus. 



Carapace parchment-like 7 



7. Longitudinal grooves on the carapace, beginning behind 



the orbits Raphonotus Rathbun 



No longitudinal grooves on the carapace Pinnotheres Latreille 



Dissodactylus S. J. Smith. 



1870. Dissodacfyliis S. J. Smith. Transact. Connecticut Ac, v. 2, p. 172. 

 1900. Ecliinophilus Rathbun. Am. Natur., v. 34, p. 590. 



The typical species is Dissodactybcs 7Litidics S. J. Smith, 1. c, p. 173, found at Panama. 

 Afterwards Miss Rathbun records it from Lower California ^) and from Peru "-). 



A second species is Dissodactylus incllitae Rathbun, 1. c, and a third Dissodactylus 

 encopei Rathbun, Bull. U. S. Fish Comm. for 1900, v. 2, 1901, p. 22, textfig. 5; both these 

 species are associated with Echinids and occur in West Indian waters. 



:) Proc. U. S. Nat. Mus., v. 21, 1899, p. 609. 



2) Proc. U. S. Nat. Mus., v. 38, 1910, p. 545, pi. 48, f. 6. 



97 



SIBOGA-F.XPEDITIE XXXIX^'. • 32 



