NASSA. 395 



Bmcinum tuberculaUiin, Turton, Conch. Diction, p. lO' (teste JettVeys from type). 

 Tritonia varicosa, Turton, Zool. Journ. vol. ii. p. 365, pi. 1 3, f. 7. 

 N^assa incrassata, var. Fleming, Brit. Anim. p. 340. 

 Bucciniirn incrassatnm, var. Brit. Marine Conch, f. 47. 

 Nussa varicosa. Brown, lUust. Conch. G. B. p. 5, pi. 4, f. 24. 



It is strange that a shell so well marked in its characters 

 shonld not have been distinguished as a species by the 

 earlier British writers : it appears to have been passed over 

 as a variety of the preceding species. 



The shell is oval-conic, not very thick, never shining, 

 often semitransparent, and painted on a dirty ochraceous 

 or mud-coloured ground, with a dark livid very narrow 

 fillet that winds below the suture ; besides which two or 

 three rarely entire (or uninterrupted) pale chestnut bands 

 (one basal, one medial, and the third, which is rarely visi- 

 ble, between the last and the infrasutural dusky line) par- 

 tially encircle the body, but are chiefly evident on the few 

 solid riblike white varices, which at irregular intervals (two 

 at most on each turn ; indeed the labial varix is occasion- 

 ally the sole one) protrude from the general surface. Nu- 

 merous, but not crowded, narrow longitudinal ribs (they vary 

 as to number, but twelve at least appear on each larger volu- 

 tion) are somewhat cancellately decussated by more closely 

 disposed spiral costellse, of which last there are somewhere 

 about ten rows on the body, four or five of which are conti- 

 nued upon the smaller turns : their intersectional points 

 are slightly nodulous. The sharply pointed spire is com- 

 posed of seven or eight short whorls, that Increase rather 

 quickly in length, are simply convex (not ventricose), taper 

 rather quickly above, and are deeply divided by the not 

 much slanting sutural line. The body is moderately 

 ventricose, and decidedly, though not considerably, shorter 

 than the spire : its basal declination is somewhat abrupt, 

 but well rounded. From two-fifths to three-sevenths of the 



