SOLARIELLA. 309 



rather close waves or folds, so low and obtuse as to be frequently 

 almost indistinguishable. The spire is conical ; apex rather blunt ; 

 apical whorl rather prominent, reddish, corneous or purplish, smooth, 

 rounded; suture impressed; whorls 5J, convex, tubular, the last 

 slightly convex beneath and carinated around the umbilicus. The 

 aperture is oblique, circular, its margins thin and arcuate ; there is 

 a slight angle at the base of the columellar lip. 



Alt. 8, diam. 9 mill. ; frequently smaller. 



New England Northward; Nova Zembla; Scandinavia; Belir- 

 ing Sn i. 



Turbo obscurus COUTHOUY, Bost. Journ. Nat. Hist, ii, p. 100, t. 

 3, f. 2. Min-f/'iritu obscura Couth. GOULD, Invert, of Mass., p. 253, 

 fig. 171 ; BINXKY'S edit., p. 283, f. 545. LECHE, Kongl. Sw. Vet- 

 Akad. Handl. xvi, p. 44, and var. intermedia, t. 2, f. 25, and cinerece 

 fonni*, p. 4"). ^[<^ch(Kroplax obscura Couth. SARS, Moll. Reg. Arct. 



Norv., p. 137, t. 9, f. 5. Trochus obscurus Couth. PHIL., Conchyl. 



Cab., t. 42, f. 3. Machacroplax obscura var. planula VERRILL, 

 Trans. Conn. Acad. Sci. v, p. 531 ( 1882), and var. carinata 

 VERRILL, 1. c., p. 532. 



Var. PLAXTLA Yorrill. 



Another form of 3/. obscura frequently occurs south of Cape Cod, 

 in 15 to 30 fins. In this the base is nearly smooth, with the radiat- 

 ing ribs obsolete, or indicated merely by bands of brownish color, 

 while the spiral lines are entirely wanting, or occur only near the 

 periphery, and often in the umbilicus, which may or may not be de- 

 fined by an angular border. The body-whorl usually has three or 

 four more or less distinct, but low, angular spiral cinguli, of which 

 the first, just below the suture, usually forms only a slight ridge on 

 the flattened subsutural band, and is often entirely absent ; the second, 

 midway between the suture and periphery, is the largest, most 

 prominent, and most constantly present ; below this there may be 2 

 or 3 evident carime, or these may be absent, or replaced by several 

 fine spiral cinguli. Transverse low ribs or undulations may be more 

 or less distinct on all the whorls, but more frequently are present on 

 the upper whorls, and obsolete, or nearly so, on the lower ones. 

 ( VerrilL} Scarcely distinct enough from obscura for a varietal name 



Var. CARIXATA Verrill. 



This has the form and the large umbilicus of M. obscura, but its 

 strong, spiral carinse and the distinct spiral carina around the um- 



