290 MARGARITA. 



M. FRiELEi Krause. PI. 66, figs. 91, 92. 



Shell thin, white, pearly within, depressed -conical ; spire obtuse; 

 whorls 4, regularly rounded, the last much dilated ; suture deeply 

 impressed; aperture rounded, outer and inner lips equally arcuate; 

 umbilicus broad, not definitely bounded, but rounding into the base ; 

 surface covered with very fine undulating spiral strise. 



Alt. 6, diam. 10 mill. 



Radula elongated, rhachidian teeth with greatly recurved apices, 

 finely denticulated, laterals narrow-falciform, uncini large, sigmoid. 



Formula 17-(l)-9-(l)-17. (Krause.) 



St. Lmvrence Bay, Behring Sea. 



M. Frielei Krause, Archiv f Naturgeschichte, 1885, p. 263, t. 

 16, f. 2 (shell and radula). 



The shell is very similar to that of M. argentata Gld., but the 

 characters of the radula are much more like that of Solariella. The 

 animal is colorless ; it has 5 epipodial cirrhi on each side, and small 

 frontal lappets. 



M. UNDULATA Sowcrby. PL 39, figs. 36-39 ; pi. 64, figs. 42, 43, 44. 



Shell umbilicate, conical, thin but rather solid, lusterless, varying 

 from a dark flesh tint to yellowish in color; surface covered with 

 fine sharply-cut spiral riblets, irregular in size, generally alternat- 

 ing larger and smaller, about 10-12 in number on the penultimate 

 whorl in large specimens, much less prominent on the base except 

 around the umbilicus. Below the suture there is a series of little 

 folds or puckerings, more or less obvious on different individuals. 

 The spire is conical, elevated, the apex minute, acute ; sutures well 

 impressed ; whorls 6, convex, the last very obtusely subangular at 

 the periphery, rather flattened beneath ; aperture very oblique, 

 nearly round ; margins simple, converging, joined by a short parietal 

 callous; umbilicus deep, rather funnel-shaped, its margin not dis- 

 tinctly angular. Alt. 8-9, diam. 10 mill. 



New England, England, Scandinavia, north to Greenland. 



Margarita nnditlata SowB. Mai. and Conch. Mag. i, p. 26, 1838 ; 

 Conch. Illust., f 4.— Gould, Invert. Mass., p. 254, f 172.— Reeve, 

 Conch. Syst., t. 221, f 4. — Sowb. in Reeve, Conch. Icon., f. 2 ; Gould, 

 edit. Binney, Inv. Mass., p. 280, f. 541. — Trochus undulatm Phil- 

 ipri Conchyl. Cab., p. 251, t. 37, f 13, 14.— Forbes & Hanley 

 Hist. Brit. Moll., ii, p. 528, t. 68, f 1, 2 ; t. 73, f 5, Q.— Turbo in- 

 carnatus Couthouy, Bost. Journ. N. H. ii, p. 98, t. 3, f 13. — Mar- 



