PURPURIFERA. MOLLUSCA. BUCCINUM. 309 



Inhabits all our muddy shores, preferring situations not exposed 

 to the surf of the open sea ; such as inlets and extended flats 

 which are drained at low tide. It is found abundantly at the con- 

 fluence of fresh and salt water, where the taste is merely brackish. 

 Professor Adams remarks, that the finest specimens he had found 

 " were growing at Nantucket, where they are as abundant as in 

 any of our continental harbours." 



No shell of equal size is so abundant on the whole Atlantic shore. 

 Specimens from Florida vary only in being smaller, more olivaceous, 

 and by having a thick, broad callus over the pillar. 



The younger shells are most likely to be collected, because the old 

 ones become very much eroded and defaced, and a greenish, mould- 

 like plant vegetates abundantly upon it. Very few, therefore, of the 

 shells usually collected, have the lines on the interior of the outer lip. 

 Kiener's figure represents an immature shell. 



Bu'cciNUM trivitta'tum. 



Shell ovate-conic, lurreled^ greenish-white^ surface wrought into 

 a net-work by elevated^ decussating lines ; sometimes loith three dark 

 bands on the lower whorl ; raised lines within the lip. 



Figure 211. 



State Coll., No. 6. Soc. Cab., No. 1498. 



Nassa triviltata, Say; Journ. Acad. Kat. Sc, ii. 231. 

 Biiccinuni trivittatum, Adams ; Bost. Joitrn. Mat. Hist., ii. 265. 



Shell ovate-conic, turreted, apex acute, greenish or yellowish- 

 white, cross-barred, so as to appear granulated, by means of prom- 

 inent, equidistant, longitudinal lines, and ten, equally regular, re- 

 volving, impressed lines on the larger whorl, and a somewhat 

 more conspicuous groove near the summit of each volution ; 

 whorls seven, flattened above, so as to present a conspicuous 

 shoulder at the suture ; in the best specimens there is a dark band 

 at the top, on the middle, and at the front of the body whorl, each 

 occupying two series of granules ; the lower line of granules on 

 each whorl is also colored ; aperture oval, terminating behind in a 

 canal formed by a dilatation of the right lip, and a fold on the left, 

 and before in a short, ascending beak which is divided from the 



