288 MARGARITA. 



only a little convex, and even the last are rather declivous. The 

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

 almost higher than broad, with simple, acute peristome. The entire 

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

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

 Greenland; Spitzbergen; Plover Bay, Beliring Sea. 

 Marg. vahlii MOLL., Jnd. Moll. Gronl., p. 8. Tr. vahlii Moll. 

 PHIL., Conchyl. Cab., p. 286, t. 42, f. 6. M. vahlii Moll., KRAUSE, 

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



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



64, figs. 39, 40, 41. 



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

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

 the sculpture becoming obsolete on the last two whorls, which 

 however usually show a few obsolete striae just above the periphery ; 

 the umbilicus has a few obscure stride 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, diarn. 15 mill.; alt. 13, diam. 22 mill.; alt. 15, diam. 21 

 mill. 



Melville Id. ; Cumberland Sound ; Greenland. 



Margarita umbilicalis BROD. AND SBY. Mai. and Conch. Mag. i, 

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

 Monog. Margarita, f. 1. PHILIPPI, Conchyl. Cab., p. 245, t. 37, f. 

 2. GEORG PFEFFER, in Naturhist. Mus. zu Hamburg, Dr. Pagen- 

 stecher's Bericht fur 1885, p. 43, f. 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 depressed, 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 



