252 INVERTEBRATA OP MASSACHUSETTS. 



found, and all doubts may thereby be removed. Should it prove a 

 distinct species, Professor Adams has proposed for it the name of S. 

 pulchella. 



FAMILY TUEBINACEA, LAM. 



Shell turreted or conoid ; aperture rounded or oblong, not spreading ; lips 

 disunited posteriorly. 



GENUS MARGARiTA, LEACH. 



Shell conical, moderately elevated ; whorls few, sub-inflated ; 

 aperture rounded., imperfect posteriorly ; lip sharp ; umbilicus deep ; 

 operculum multi-spiral ; the nucleus central. 



MARGARITA CINE'REA. 



Shell low-conical, thin, ash-colored, umbilicated, with four to six 

 elevated and numerous smaller revolving ridges, and regular, erod- 

 ed, elevated lines of growth. 



State Coll., No. 128. Soc. Cab., No. 2278. 



Turbo cinereus, COUTHOUY; Bost.Journ. Nat. Hist., ii. 99, pi. 3, f. 9. 

 Trochus costalis, LOVE^N ; in letters. 



Shell small, thin, of a low conical or pyramidal shape ; color a 

 dull ashy-white, sometimes tinted with green ; whorls five to 

 seven, convex, and rendered angular by prominent, irregularly dis- 

 posed revolving ridges, of which from four to six are more ele- 

 vated, with less conspicuous intervening ones ; and the lowest of 

 these elevated ridges forms a limit, at which the whorl slopes ab- 

 ruptly, and presents a broad, slightly convex base, marked with 

 fine, equal, and equidistant revolving lines ; the whole surface is 

 also covered with crowded, very fine, and distinctly prominent 

 lines of growth ; the umbilicus is broad and deep, and bounded by 

 the last revolving line, which forms an angle terminating at 

 the most anterior point of the otherwise circular aperture, 

 and here causes an angular prolongation; outer lip regularly 

 curved, sharp, finely scolloped ; it rises on the left margin, and 

 terminates just behind the umbilicus, slightly expanding and par- 



