88 AMERICAN MARINE CONCHOLOGY. 



1. M. occidentalis, Mighels and Adams. Fig. 109. 



(Trochus.) Bost. Joum. Nat. Hist., iv. 47, t. 4, f. 1G. 1842. 



Margarita alabastrum, Beck. 



Shell small, rather solid, subtranslucent, pale horn-color, with 



light brown revolving carinas, three in number on the upper 



whorls, and from four to six on the body-whorl ; whorls seven, 



convex, with distinct sutures ; spire small ; the body-whorl large, 



with coarse revolving striae around the indented umbilical region. 



Height 12.5, diam. 10 mill. 



Maine. (Eur.) 



2. M. cinerea, Couthouy. Fig. 170. 



(Turbo.) Bost. Journ. Nat. Hist., ii. 99, t. 3, f. 9. 1838. 



Shell small, thin, pyramidal ; whorls five to seven, with several 



revolving ribs, the central one largest ; umbilicus broad and deep ; 



lip sharp; aperture circular, slightly reflected over the umbilicus. 



Ashen-gray or greenish. 



Height 12.5, diam. 10 mill. 



New Engla nd. ( Eur. ) 



3. M. obscura, Couthouy. Fig. 171. 



(Turbo.) Bost. Journ. Nat. Hist., ii. 100, t. 3, f. 2. 1838. 



Depressed, conical, solid; spire obscure, reddish-brown, base 

 ash-colored ; whorls angulated by two or three revolving ridges ; 

 lines of growth coarse ; aperture circular ; pearly within. 



Height 10, diam. 15 mill. 



New England. (Eur.) 



4. M. varicosa, Mighels and Adams. Figs. 172, 178. 



Bost. Journ. Nat. Hist., iv. 46, t. 4, f. 14. 1842. 

 Margarita acuminata, Mighels and Adams, ib. f. 15. 1842. 



Shell small, conical, thin, dingy white or drab-color; whorls 

 four, convex, with numerous longitudinal oblique ribs, and 

 crowded revolving striae. Suture distinct, subcanaliculate ; um- 

 bilicus rather large and deep, bounded by two rather rugged 

 varices. Aperture circular, lip sharp. 



Height 6.25, diam. 6.25 mill. 



New England, nortkicards. (Eur.) 



31. acuminata is the young of this species. Fig. 178 repre- 

 sents it. 



5. M. minuttssima, Mighels. Fig. 173. 



Bost. Journ. Nat. Hist., iv. 349, t. 16, f. 5. 1843. 

 Shell very minute, subovately globose ; whorls three, convex, 



