DORVILLEA CRASSA. 339 



These forms occur mostly between tide-marks, and are commonly found 

 under stones, or in but shallow water. In their alimentary canals have been 

 found such debris as sand, diatoms, spicules of sponges and fragments of crusta- 

 ceans. The forms observed appear to be comparatively hardy in captivity. 

 Some have been seen to swim freely {e.g., D. rudolphi and D. kefersteini, fide 

 Eisig and Mcintosh) with a wriggUng motion, or to crawl about actively. Ophryo- 

 trocha puerilis has been found in the body-cavity of Cucumaria plance at Naples 

 by Monticelli (Monit. zool. Ital, 1892, 3, p. 250). 



Key to Genera. 



a. With two articulated or moniliform tentacles and two palpi Domllea Parfitt. 



aa. With four similarly formed tentacles, or processes, which are simple and non-articulated. 



Ophrijolrocha Claparede and Me ;znikow. 



Synonymy of Genera. 



Staurocephalus Grube (1855) has long been used for the more important 

 genus of this family, as has Staurocephahdae for the family; but unfortunately 

 Staurocephalus was previously used in Crustacea (1846). Dorvillea Parfitt 

 (1866, type D. lohata = Staurocephalus ruhrovittatus Grube) is the next name 

 applicable to the genus. This differs in spelHng from DorvilHa, apphed by 

 Leach to a lepidopterous genus in 1815, and must therefore stand as a distinct 

 name. 



Paractius Levinsen (1879) is here included under Ophryotrocha Claparede 

 (0. puerilis Claparede and Mecznikow, the type of the latter being, in fact, 

 possibly the same as P. littoralis Levinsen, the type of the first), — as is also 

 Stauroceps Verrill (1900), proposed as a subgenus of Stauronereis. 



Dorvillea Parfitt. 



Zoologist, 1866, ser. 2, 1, p. 113. 



Staurocephaltis Grube, Archiv. naturg., 1855, 21, p. 97. 



Anisoceras Grube, Vid. meddel., 1856, p. 60. 



Prionognalhus Keferstein, Zeitschr. wiss. zool., 1862, 12, p. 99. 



Stauronereis Verrill, Trans. Conn. acad. sci., 1900, 10, p. 647. 



Teleonereis Verrill, Ibid., 1900, 10, p. 648. 



Dorvillea crassa, sp. nov.^ 



Plate 62, fig. 6, 7; Plate 63, fig. 1. 



The general color is dull brown, with the parapodia scarcely paler. No 

 markings. 



1 crassus, stout. 



