90 LITTORINID.E. 



Rissoa punctura , Brown, Illiist. Conch. G. B. pi, 9, f. 43. 



„ appromma, BiiowN, Illiist. Conch. G. B. p. 12, pi. 9, f. 42 ? 



We consider the Turbo punctura and reticulatus of Mon- 

 tagu to be merely two conditions of the same shell, the 

 outer lip in the former not being marginated at that stage 

 of growth. We have preferred the appellation punctura., 

 not on account of its two pages of priority (since the actual 

 date of publication was the same for both), but because the 

 description of the latter was not sufficiently perspicuous 

 to enable naturalists to identify the object intended ; hence 

 Bemiii, inconspiciia, &c. are often queried for that shell in 

 the cabinets of our most scientific collectors. Neither the 

 pen nor the pencil of Adams have clearly defined the 

 species he meant to pourtra}-. 



The shell is rather thin, translucent, more or less glossy, 

 and of a conic or oval-conic form. In general it is of an 

 uniform yellowish white, but when perfectly fresh is girt 

 towards the base of the body with a tawny narrow zone, 

 from whence, as well as from the suture, emanate rather 

 distant streaks of the same hue, that do not usually touch 

 each other in the middle of the whorl. A coloured si)ot, 

 marking the termination of the zone, is almost always per- 

 ceptible near the base of the outer lip, behind which, near 

 the top, may usually be seen, likewise, an oblique coloured 

 segment of a circle. The surface is reticulated or very 

 delicately cancellated by longitudinal and spiral thread- 

 like lines, which are so slightly raised that worn individuals 

 appear to be merely indented with regular and closely 

 disposed series of puncfures. The longitudinal threads are 

 extremely numerous, and usually become more or less in- 

 distinct near the base of the body ; the spiral ones, which 

 extend to tlie extreme base, are also numerous, there being 

 generally twelve or fourteen of them upon the body, and 



