MARGARITA. 283 



slightly angular; the next above is elevated, but the uppermost, and 

 frequently the two uppermost, are not elevated above the succeed- 

 ing whorl, so that the apex is obtuse ; everywhere covered 

 with crowded and very fine revolving lines ; suture deep ; ^ '^ 

 aperture circular ; lip sharp, simple ; interior pearly and ^p^ ^-^ 

 iridescent ; umbilicus moderately large. Length, one ^j. argentata. 

 tenth of an inch ; breadth, one eighth of an inch. 



Found in fishes caught off Cape Ann and Cohasset, in consider- 

 able numbers. Fishing Banks ( IVillis) ; Grand Manan to Cape 

 Cod (^Stimpson). 



It is the smallest of the species of this genus that we find. It is 

 most obviously distinguished from small specimens of the last spe- 

 cies by its dead surface, which may w^ell be compared to chased 

 silver ; and, on a more intimate examination, it is found to have 

 more uniform and decided revolving lines, and its spire is more 

 elevated. 



I was at first disposed to regard it as the M. carnea^ Lowe (Zool. 

 Journ. ii. 107, pi. 5, figs. 12, 13, 132). But, in the following essen- 

 tial characters belonging to that, it differs from our shell, viz., an 

 acutely pointed spire, an angular aperture, and a uniform yellowish 

 flesh-color. The revolving lines, too, are said to be elevated and 

 sub-distant, terms which allow of much latitude of meaning, but 

 which we should not be likely to apply to the crowded, microscopic 

 lines on our shell. They appear cpiite conspicuous on the figure 

 quoted. The young of M. undulata would answer better to that 

 description. If it is not M. carnea, it has not been described ; Mr. 

 Sowcrby hesitates to call it so. 



Margarita obscura. 



Fig. 171*. 



Shell depressed-conical, solid ; spire obscure, reddish-brown, base ash-colored ; 

 whorls angulated by two or -three revolving ridges; lines of growth coarse; aper- 

 ture circular, pearly within. 



Ttirho ohscurus, CouTiiouY, Bost. Journ. Nat. Hist. ii. 100, pi. 3, fiir. 2. 



Margarita obscura, Gould, Inv. 1st etl. 253, fig. 171*. — StiiMpsox, Clieck Lists, 4. 



Shell small, solid, orbicular, low-conical, of a dull reddish-brown 

 above, and of a light ash color at base ; whorls five, convex, and 

 rendered angular about the middle by a prominent revolving ridge ; 

 on the lower whorl are often one or two less conspicuous ridges, 



