/: 



246 



Cryptophrys Rathbun. 



1S93. Cryptophrys Rathbun. Proc. U.S. Nat. Mus., v. 16, p. 250. 



Only one species is known, Cryptophrys conchanim Rathbun, 1. c. ^), which inhabits the 

 coast of Lower California and lives in the mantle-cavity of Mya ai-cnaria and Cardita. 



Xanthasia White. 

 Literature: Alcock, Journ. As. Soc. Bengal, v. 69, prt 2, 1900, p. 340 — 341. 



The typical species is the very characteristic Xanthasia nutrigera White; its records in 

 literature are enumerated by Alcock, 1. c. Its original locality are the Philippines, but afterwards 

 it has been recorded from the Fiji Islands, New Caledonia, Mozambique, Mergui Archipelago, 

 Andamans, New Guinea and Australia. 



A second species is Xanthasia ivhitci de Man ") from the Mergui Archipelago. Like 

 the typical form it inhabits the mantle-cavity of Lamellibranchs ; the lateral margins of the 

 carapace are not thin, but thickened, they are separated from the likewise thickened posterior 

 margin, and the tubercle in the middle of the carapace is not shaped like a mushroom and ill-defined. 



Diirckheimia de Man. 



1889. Diirckheimia (Riippell in M.S.) de Man. Zool. Jahrb., Syst., Bd 4, p. 442. 



The genus has been founded on Diirckheimia carinipes de Man, from the Red Sea. 

 It presents a rounded, elevated ridge parting from the middle of the posterior margin of the 

 carapace, but disappearing in the anterior third of the carapace. In a second species, Dtirck- 

 heimia caeca Burger ^) from the Philippines, this median ridge is thinner, crest-like, and continued 

 forward to the deep notch in the anterior margin of the carapace. 



Scleroplax Rathbun. 



1893. Scleroplax Rathbun. Proc. U.S. Nat. Mus., v. 16, p. 250. 



The only species is Scleroplax granulata Rathbun, I.e., p. 251, from California*). 



RaphonotuS Rathbun. 



1851. Fabia Dana. Am. Journ. Sc. (2), v. 12, p. 290 (praeocc). 

 1897. Raphonotus Rathbun. Proc. Biol. Soc. Washington, v. 11, p. 166. 



This genus again contains only a single species, Fabia subquadrata Dana ") from Oregon 



1) See also Holmes, Occas. Pap. Californ. Ac. Sc, v. 7, 1900, p. 96; Rathbu.\, Havriman Alaska Exp., v. 10, 1904, p. 188; 

 Weymouth, Leland Stanford Jr. Univ. Publ., d» 4, 1910, p. 60. 



2) Journ. Linn. Soc. London, v. 22, iSS'S, p. 106, pi. 7, f. i. 



3) Zool. Jahrb., Syst., Bd. 8, 1895, p. 385, pi. 9, f. 33, pi. 10, f. 31. 



4) See also Holmes, Occas. Pap. Californ. Ac. Sc, v. 7, 1900, p. 94; Rathbun, Haniman Alaska Exp., v. 10, 1904, p. 1S8; 

 Weymouth, Leland Stanford Jr. Univ. Publ., n" 4, igio, p. 59, textfig. 8. 



5) Proc. Ac. Nat. Sc. Philadelphia, 1851, p. 253; U. S. Expl. Exp., Crust., 1852, p. 383, pi. 24, f. 5; Holmes, (part.), Occas. 

 Pap. Californ. Ac. Sc, v. 7, 1900, p. 87; Raphonotus subquadratus Rathbun, Harriman Alaska Exp., v. 10, 1904, p. 186; Weymouth, 

 Leland Stanford Jr. Univ. Publ., n« 4, 1910, p. 55, textfig. 2. Holmes, according to Miss Rathbun, confounded with R. subquadratus 

 another apparently new species, which is called R. lowei. Raphonotus is very common in the mantle cavity of the common mussel 

 {Mytilus edulis) and in the folds of Lmapina craiulata (a Gastropod allied to Fissurelia). 



98 



