310 INVERTEBRATA OF MASSACHUSETTS. 



body of the shell by a deep groove ; outer lip sharp, and scol- 

 loped by the revolving lines ; pillar regularly arched, with a dis- 

 tinct, revolving ridge bordering the canal, and covered, to a con- 

 siderable extent, with greenish enamel ; throat white, or with 

 brown bands corresponding to those on the outside ; a few 

 elevated lines within, not reaching the margin ; operculum horny, 

 of an irregular, three-sided shape, one half its edge sharply ser- 

 rated. Length j\ inch, breadth j\ inch, divergence 45°. 



Found in a worn state on most of our sea-beaches, and oc- 

 casionally alive at Chelsea. Dr. William Prescott, of Lynn, 

 found it alive, in abundance, at low-water mark, on Phillips's 

 Beach ; Professor C. B. Adams found it at New Bedford, and 

 says it is abundant at Nantucket, on the inner side of Brant Point, 

 and also on the south shore, less abundant, but larger. 



No other shell inhabiting our coast bears any near resemblance to 

 this. Its sculpture is like that of B. marginulatum from the Indian 

 Seas, and its whole appearance is very much like that of Kiener's 

 B. Roissyi from the Australian Seas. It undergoes considerable varia- 

 tion. The three lines of rufous color which suggested its specific 

 name are very rarely seen on shells in this latitude ; and then, again, 

 we find all the revolving lines more or less colored. In some, the two 

 sets of lines are precisely alike in size and distance ; in others, the 

 longitudinal lines are much the most distant, and become more like 

 undulating folds. These last may be regarded as a well-marked 

 variety ; they are also more acutely pointed, and the shoulder at the 

 suture is more rounded. Specimens from Nantucket have the inner 

 margin thickly coated to a considerable extent with enamel, while 

 those found near Boston have none. I have a specimen -^^s of an inch 

 long. 



Bu'cCINUM VIBEX. 



Shell thick^ short, ovate-conic ; surface checked with waving 

 folds and revolving lines, and alternately zoned with light and dark 

 color ; lip thickened and toothed within ; pillar with a broad and 

 thick callus, granulated at base. 



Figure 212. 



State Coll., No. 5. See. Cab., No. 576. 



