RISSOIA. 347 



Atlantic Coast of Europe, f Mediterranean Sea, Nahant, Mass., 

 Halifax, N. S. 



The synonyms include R. minutissima, Mich., R. communis, 

 Forbes, R. semicostata, Turton, Pyramis discors and candidus, 

 Brown, R. gracilis, Macg., R. Marionw, Macg. The American 

 localities are for R. multilineata, Stimpson (fig. 73), which appears 

 to be identical. 



Var. LIKATA, Watson. 



Ribs and basal spiral sculpture stronger. 



Madeira. 

 R. SAXATILIS, Moller. PI. 64, figs. 87, 88. 



Imperforate, thin ; whorls 4, very convex, with deep suture, 

 spirally cingulated ; yellowish white, translucent. Length, 3 mill. 



Greenland, Behring's Sea, New England. 



R. arctiea, Loven, and, I think, R. leptalea, Verrill (fig. 88), 

 who has so named a single specimen occurring in New England 

 waters, are synonyms. 



R. ACULEUS, Gould. PL 70, fig. 64c. 



Imperforate, but with a slight depression partly covered by the 

 inner lip, apex blunt ; whorls 6, moderately convex, with regular, 

 crowded microscopic, spiral lines ; aperture simple, entire ; light 

 yellowish horn color. Length, 3'5 mill. 



New England. 



Some European authors consider this a synonym of R. striata, 

 Mtg. 



R. AFFINIS, Jeffreys. PL 66, fig. 39. 



Rather thin, semitransparent, glossy, whitish ; whorls 4, slightly, 

 indistinctly spirall) striate ; apex blunt; outer lip thin, somewhat 

 expanded. Length, 2'7/> mill. 



Vigo Bay. 



Has fewer whorls than R. ztriata or R. aculeus, and they are less 

 convex than in R. saxatiti*. 



R. ARENARIA, Mighels and Adams. PL 63, figs. 74, 75. 



Whorls 6, convex, longitudinally subplicate, minutely spirally 

 striate, suture impressed, whitish. Length, 2*5 mill. 



Greenland, Canada, Maine, Spitzbergen. 



Stimpson changed the name to R. Mighelsi on account of Turbo 

 arenarius (Mtg.?) Maton, Turton, etc., which, however, isOdostomia 

 deeussata. R. exarata, Stimpson, is a synonym ; but the figure of 



