NO. 8 HAIG: THE ATLANTIC GALATHEIDEA 29 



Remarks. — The name macrocheles, long in use for this species, is 

 unfortunately not available, Porcellana macrocheles Gibbes, 1850, being 

 a primar}^ homonym of Porcellana macrocheles Poeppig, 1836 (= 

 Petrolisthes violaceus (Guerin), Chile and Peru). Gibbes himself 

 pointed out (1854, p. 6) that Porcellana macrocheles had already been 

 employed, but he believed that his own use of the name was valid since 

 P. macrocheles Poeppig was a synonym of another species. However, 

 this position is not tenable according to current nomenclatorial practice 

 (1950, Bull. Zool. Nomen., vol. 4, p. 119). Mr. W. I. Follett of the 

 California Academy of Sciences kindly verified this fact for the writer. 

 A new name, Polyonyx gibbesi, is here proposed as a substitute. 



Miiller (1862, p. 194, footnote; 1863, p. 47, footnote), in a dis- 

 cussion of various Brazilian crabs, made the following statement: 

 "Another Porcellana {P. Creplinii, n. sp.) is still more singular in its 

 mode of life; it resides in pairs in the tube of Chaetopterus pergament- 

 aceus." [Quoted from the 1863 translation.] This description is enough 

 to identify it as a Polyonyx; in a later paper (1870, p. 54) Miiller 

 called it Porcellana (Polyonyx) creplinii and gave further notes on its 

 habits, stating that according to a communication from A. Milne Ed- 

 wards it is close to Polyonyx biunguiculata (Dana). The crab cannot 

 be identified to species from the information available. It is not listed in 

 the catalogues of Brazilian crabs prepared by Smith (1869) and Moreira 

 (1901). Dr. Alceu Lemos de Castro of the Museu Nacional, Rio de 

 Janeiro, informed the w^riter {in litt.) that he believes it to be identical 

 with Polyonyx macrocheles (Gibbes), and that he has seen a museum 

 specimen which was collected at Ilha de Sao Sebastiao, Brazil. 



The observation on the coast of Brazil of "two couples of crabs in 

 the tube of a very long annelid" was noted by van Beneden (1876, p. 

 20). This may have been Polyonyx gibbesi, although it is as likely to 

 have been the brachyuran Pinnixa, species of which also occur in Chae- 

 topterus tubes. 



Crabs of this species are occasionally found living free along shore 

 and in shallow water, under stones or on sand ; the Velero III specimen 

 was taken in 1-7 fathoms on a mud and fine sand bottom. Usually, how- 

 ever, they occur in tubes of annelids of the genus Chaetopterus. This 

 commensal relationship has been reported for several other Polyonyx 

 species in various parts of the world. The habits and behavior of P. 

 gibbesi were discussed by Enders (1905) and Pearse (1913). 



Although it is primarily a warm-water form, the species appears to 

 be established as far north as Woods Hole, Massachusetts. According 

 to Faxon (1879), who collected and described zoeae from Narragansett 



