322 CERITHIID^. 



lines there are about six on the lower whorl but one, five on the 

 next above, and so on ; besides these, on the anterior whorl are 

 about six raised revolving lines about the base, partially 

 Fig. 590. granulated ; suture distinct, with the series of granules next 

 below it rather largest, so as to form a slight shoulder ; ap- 

 erture oblique, rounded, and flaring, about one quarter the 

 length of the shell, broad anteriorly ; outer lip sharp, mod- 

 B m rwn ^^'-''^ ^'^ ^^^® rcvolvlug liues ; inner margin angular-concave, 

 with a plate of enamel, not pressed close upon the body 

 whorl, uniting the two lips above, and forming an umbilical fissure 

 below ; canal a mere oblique fissure or notch, not prolonged for- 

 ward so far as the lip ; operculum horny, ovate, apex at the centre 

 of the broader part concave outwardly, with four or five spiral 

 turns. Length, three tenths of an inch ; breadth, one tenth of an 

 inch ; divergence, twenty-eight degrees. 



Found very abundantly at Nantucket, Martha's Vineyard, New 

 Bedford, &c. It has not been found to my knowledge within or to 

 the north of Cape Cod. Pictou {Datvson^ ; Halifax (^Willis}. Its 

 proper station is on sea-weed, stones, and marine bodies, about low- 

 water mark. The young are sometimes seen in such numbers as 

 to conceal the sand beneath them. Tliese are always reddish-black, 

 with a very different aperture. It seems not to attain its growth 

 the first season, and the second year's growth is usually distinctly 

 indicated by its much lighter color. 



The name given by Colonel Tottcn, at my suggestion, is preoc- 

 cupied by an English species.* Its wide expanded mouth, with 

 scarcely anything like a canal, renders its claim to a place in the 

 genus Cerithinm rather equivocal. These characters, with its sculp- 

 ture, distinguish the species. 



Bittium Greenii. 



Fig. 184. 



Shell small, reddish-black, tumido-conie, elongated, Avith longitudinal ridges 

 and revolving lines ; canal very deep and very short, slightly curved. 



Cerithium Greenii, Adams, Bost. Journ. Nat. Hist. ii. 287, pi. 4, fig. 12. — Gould, Inv. 



1st ed. 279, fig. 184. 

 Bittium Greenii, Stimpson, Check Lists, 5. 



Shell small, elevated-conic, sloping somewhat abruptly above the 

 middle, to a prolonged, pointed apex ; whorls ten or twelve, flat- 



* In the genus Cerithium. — W. G. B. 



