266 



Pinnixa White. 



1846. Pinnixa White. Ann. Mag. Nat. Hist., v. 18, p. 177. 

 1876. Tubicola Lockington. Proc. Californ. Ac, v. 7, p. 55. 



This genus contains 1 8 species, which are remarkable by their transverse carapace 

 (generally twice as wide as long), by the penultimate pair of legs being usually much larger 

 than the last pair, and by the shape of the maxillipeds, the palp of which is very bulky, 

 propodus and dactylus being dilated and the former largely projecting beyond the insertion of 

 the latter. There is often a transverse crest across the cardiac region of the carapace. 



As far as is known, all species are commensals of worm-tubes (hence also the term 

 Tubicola used by Lockington). In general appearance and in habits these species exhibit a 

 striking resemblance to the Hexapodmae, which are also known to inhabit tubes of Annelids. 

 We ignore whether this remarkable resemblance be due to a real phylogenetic affinity or to 

 similarity of conditions of life. 



Species living at the Atlantic coasts of America : • 



P. cylindrica (Say) nee Stimpson, S. J. Smith. 



18 18. Pinnotlieres cylindricum Say. Journ. Ac. Sc. Philadelphia, v. i, p. 452. 



1846. Pinnixa cylindrica White, 1. c. 



1860. Pinnixa laevigata Stimpson. Ann. N. York Lyceum, v. 7, p. 68. 



Hab. United States. 



P . monodactyla (Say), 1. c, p. 454. Hab. United States. 



P. sayana Stimpson, 1. c, p. 236. 



Pinnixa cylindrica S. J. Smith nee Say. 



Hab. United States. 



P. chaetopterana Stimpson, 1. c, p. 235. 



Pinnixa cylindrica Stimpson, 1. c, p. 68, nee Say. 



See also: Pearse, Biol. Buil. Woods Hole, Mass., v. 24, 191 3, p. 102, figs. Hab. 



United States. 



P. niinida Rathbun. Buil. U. S. Fish Comm. for 1900, v. 2, 1901, p. 21, textfig. 4. Hab. 



Majaguez Harbour, Porto Rico. 



P. brevipollex Rathbun, Proc. U. S. Xat. Mus., v. 21, 1899, p. 605, pi. 43, f 6. Hab. Gulf 



of San Matias, Argentina. 



This species, as the author states, is nearly related to P. monodactyla, bat its carapace 



is proportionately broader. 



The following species occur at the coast of California ') : 

 P. occidentalis Rathbun. 



1893. Rathbun, Proc. U. S. Nat. Mus., y. 16, p. 248. 



1900. Holmes, Occas. Pap. Cahforn. Ac. Sc, v. 7, p. 89. 



1904. Rathbun, Harriman Alaska Exp., v. 10, p. 187. 



1910. Weymouth, Leiand Slanford Jr. Univ. Publ., n" 4, p. 56, textfig. 3. 



l) K key to all the Californian species is given by Weymouth (Leiand Stanfoid Jr. l'niv. Publ,, n" 4, 1910, p. 55). 



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