RissoiA. 347 



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

 Halifax, N. S. 



The synonyms include R. minntissima, Mich., B. communis, 

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

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

 localities are for R. 7mdtilineata, Stimpson (fig. 73), which appears 

 to be identical. 



Var. LiRATA, Watson. 



Ribs and basal spiral sculpture stronger. 



3fadeira. 

 R. SAXATiLis, MCiller. 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, Netv England. 



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

 who has so named a single si^ecimen occurring in New England 

 waters, are synonyms. 



R. AcuLEus, Gould. PI. 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 simjDle, entire; light 

 yellowish horn color. Length, 3'5 mill. 



Neiv England. 



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

 Mtg. 



R. AFFiNis, Jefl^i-eys. PI. 66, fig. 39. 



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

 indistinctly spirally striate; apex blunt; outer lip thin, somewhat 

 expanded. Length, 2'7o mill. 



Vigo Bag. 



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

 convex than in R. saxatilis. 



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



Whorls 6, convex, longitudinally subplicate, minutely spirally 

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



G-reenland, Canada, Maine, Spitzbergen. 



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

 arenarius (jNItg. ?) Maton, Turton, etc., which, however, is Odostomia 

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



