284 TROCHiDj;. 



and numerous very fine lines ; on the base these are so faint as to 

 be usually imperceptible without a magnifier ; these, with rather 

 coarse lines of growth, somewhat prominent at intervals, 

 IS- o o. q|-|.^j^ produce an indented or cellular appearance on the sur- 

 face ; umbilicus large and deep, bounded by a sharp, angu- 

 lar ridge ; aperture circular ; lip simple and sharp ; within iri- 

 descent ; o})erculum horny, multi-spiral. Height, five tenths 

 of an inch ; diameter of base, seven twentieths of an inch. 



Found rather plentifully in fishes caught off Nahant. All of New 

 England coast {Stimpson) ; Fishing Banks (^Willis}. 



It has a general resemblance to M. cinerea, but it is more solid, 

 less elevated, less angular, revolving lines fewer and less elevated, 

 the base smoother, the aperture more sini|)le and circular, and the 

 color very different. 



It may perhajjs be identical with 31. costellata, Sowerby, described 

 in the " Malacological and Conchological Journal," No. 1, and fig- 

 ured in his " Conchological Illustrations " (Margarita), fig. 15. On 

 inspection, Mr. Sowerby, though not having his shell at hand for 

 comjjarison, regards it as distinct from M. costellata. 



When the exterior is worn off, the shell beneath is found to be of 

 a brilliant silvery lustre, with crimson reflections, rendering it one 

 of the most attractive shells found in our waters. 



Margarita acuminata. 



Shell small, orbiciilar, thin, whitish ; spire pointed ; whorls four, rounded, 

 smooth; suture strongly impressed ; aperture orbicular, iridescent within; um- 

 bilicus small. 



Marcjarltn acumhmta, Mir.iiEi.s and Adams, Best. Journ. Nat. Hist. iv. 40, pi. 4, fig. 15 

 (1842). — Stimpsox, Check Lists, 4. 



Shell, small, orbicular, sub-conical, thin, of a grayish-white or 



russet color ; spire acuminate ; whorls four, Avell rounded, smooth, 



covered with a thin, semi-transparent c]:)idermis ; stria) of 



Fig. 546. ^ , 



^x growth very fine and compact ; suture well impressed ; aper- 



^^ ture orbicular, considerably oblique, beautifully iridescent 



j^_ „,„. within ; operculum horny, spiral. Height, twenty-five hun- 



minata. (^YQiWa?, of au luch ; diameter, twenty-six hundredths of an 



inch ; divergence, eighty degrees. 



Gulf of St. Lawrence, taken from the stomach of a codfish, by 

 Mr. Foster, in the summer of 1841. Only a single specimen was 

 found, which is in the cabinet of J. W. Mighels. 



