NASSA. 365 



er's B. Ruissjji from the Australian Seas. It undergoes consider- 

 able variation. Tlie 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 dis- 

 tance ; in others, the longitudinal lines are much the most distant, 

 and become more like nndnlating folds. These last may be re- 

 garded as a well-marked variety ; they are also more acutely 

 pointed, and the shoulder at the suture is more rounded. Speci- 

 mens 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 nine tenths of an inch long. 



[Animal whitish, sparsely dotted with pale lilac ; foot slightly 

 bifid behind with two erect subulate processes. Very active. Comes 

 out of the sand towards low-water mark in a minute or two after 

 the water passes over them. 



Nassa vibex. 



Fig. 212. 



Shell thick, short, ovate-conic ; surflice checked with waving folds and revolv- 

 ing lines; and alternately zoned with light and dark color; lip thickened and 

 toothed within; pillar with a broad and thick callus, granulated at base. 



Nassa vibex, Say, Jonrn. Acad. Nat. So. ii. 231 (1822) ; Amer. Conch pi. 57, fig. 2 (18.34). 



— STiMPSO>f, Check Lists, 5. 

 Biiccinum vibex, Ad.\ms, Best. Journ. Nat. Hist. ii. 2G4. 



Shell solid, -short, ovate-conic, of an ashy-white color ; whorls six, 

 suture very fine ; body Avhorl with about twelve undulating folds 

 or ribs, crossed by about ten elevated lines, most distinct 

 on the ribs ; the space between the two upper lines is more 

 deeply indented, forming pits between the ribs ; a pale-red- 

 dish zone encircles the top, the middle, and generally the 

 base of this wh;>rl, the upper one and the ribs being con- 

 tinued to the apex ; aperture oval, outer lip thickened with- ^' '"'"'^' 

 out and within, with four or five teeth within ; pillar very concave, 

 callus abundant, with a few granules at its termination ; canal very 

 short, separated from the body by a furrow. Length, half an inch ; 

 breadth, three tenths of an inch ; divergence, sixty-seven degrees. 



Specimens of this shell are rare, and usually have a chalky as- 

 pect. They have been found only to the south of Cape Cod. Mr. 



