288 MARGARITA. 



only a little convex, and even the last are x-ather declivous. The 

 umbilicus is narrow, not sharply bounded ; the aperture circular, 

 almost higher than broad, with simj^le, acute peristome. The entire 

 shell is completely smooth, very shining, transparent, pearly-colored. 

 The inside glitters with rainbow tints. Diam. 1-H lines. (Phil.) 

 Greenland; Spltzhergen ; Plover Bay, Behring Sea. 

 Marg. vahlii Moll., Ind. Moll. Gronl., p. 8. — Tr. vahlii Moll. 

 Phil., Conchyl. Cab., p. 286, t. 42, f. 6.— 31. vahlii Moll., Krause, 

 Archiv. f. Naturg. 1885, p. 261. 



M. UMBILICALI8 Broderip & Sowerby. PI. 39, figs. 61, 62, 64 ; pi. 



64, figs. 39, 40, 41. 



Widely, openly vimbilicate, depressed-conical, thin, brownish- 

 yellow ; surface polished, shining, the inner whorls closely lirulate, 

 the sculpture becoming obsolete on the last two whorls, whicli 

 hoAvever usually show a few obsolete strise just above the periphery ; 

 the umbilicus has a few obscure strite within, or none; the spire is 

 elevated, apex minute, subacute ; sutures deeply impressed ; whorls 

 about 6, convex, the last rapidly increasing, very wide ; aperture 

 oblique, subcircular, nacreous inside ; peristome simple, terminations 

 converging, connected by a short parietal callous ; umbilicus pro- 

 found, funnel-shaped. 



Alt. 11, diam. 15 mill.; alt. 13, diam. 22 mill.; alt. 15, diam. 21 

 mill. 



Melville Id. ; Cumberland Sound ; Greenland. 



Margarita umhilicalis Brod. and Sby. Mai. and Conch. Mag. i, 

 p. 26, 1838 ; Conch. 111., f. 5. — Sowb. in Reeve, Conch. Icon, xx, 

 Mouog. Margarita, f. 1. — Philippi, Conchyl. Cab., p. 245, t. 37, f. 

 2. — Georg Pfeffer, in Naturhist. Mus. zu Hamburg, Dr. Pagen- 

 stecher's Bericht fiir 1885, p. 43, £ la, b, c (1886). 



This well-marked form is characterized by its lirate upper 2 or 3 

 whorls, large size, and broadly conoid contour. The specimens 

 before me have no more exact locality than " Greenland." 



M. vorticifera Dall. PI. 59, figs. 48, 49, 50. 



Shell de})ressed, with 3 flattened, rapidly expanding whorls, which 

 have a tendency in old individuals to overhang the suture anterior 

 to them ; the upper surface is traversed by numerous slender slightly 

 elevated revolving threads, which are crossed by faint lines of 

 growth. Outer edge of whorls subcarinate. The basal surface is 



