108 Mr. W. Clark on the Rissoa rubra. 



is so discordant with the animal now presented, that one would 

 almost think some other had been inadvertently observed ; 

 perhaps a young example of the more tumid red-brown variety 

 of the Rissoa ulvce. I judge so, because authors describe their 

 animal with very long and setaceous tentacula, whereas the true 

 Rissoa rubra has those organs particularly short and smooth. 

 M. Philippics account is the best, but sadly deficient in the prin- 

 cipal peculiarities of the animal. I think malacologists will be 

 glad of a somewhat enlarged description. 



Barleeia rubra, nobis. 

 Rissoa rubra, auct. 



Shell. — The colour is plain red-brown, smooth or slightly 

 wrinkled, of 4i to 5^ tumid volutions, which form a rapidly in- 

 creasing cone. Aperture oval, entire, contracted above, rounded 

 basally, outer margin sharp, without the callous pad of the 

 Rissoee. Axis j'oth, diameter jyth of an inch. 



Animal. — The mantle is plain, even with the margin of the 

 shell, and without the filament seen at the upper angle of the 

 aperture in many of the Rissoce. Rostrum very short, not cor- 

 rugated nor capable of much extension, brindled above with dark 

 smoke-coloured, fine irregular close-set lines, below of pale yel- 

 low ; buccal disk of the same colour, of small area, crosially and 

 vertically cloven, containing the usual masticatory processes of 

 the Littorinidce ; neck dark, but not so much so as the rostrum, 

 quite plain and without appendages. Tentacula very short, 

 strong, broad, not in the least setaceous, with perfectly rounded 

 somewhat spatulate extremities ; they are not vibrated on the 

 march : colour very pale yellowish white, with a line of sulphur- 

 coloured beads or minute flakes running centrally from base to 

 point : eyes very large, black, fixed on bright sulphur inflations 

 at the external bases. Foot an elongated, rather narrow oval, 

 rounded anteally, labiated, with scarcely perceptible auricular 

 points, posteally rounded, emarginate in the centre of its termi- 

 nation ; colour in the middle of the upper part confused flake- 

 white, margined with a belt of pale smoke hue ; sole pale yellow, 

 with a decided depressed longitudinal line on the centre of the 

 posterior half, not constricted under the slight auricles as in 

 Rissoa, and not so slender ; the operculigerous lobe is small, 

 very little alated anteriorly, but expands below into a dark, flat, 

 arcuated membrane ; no cirrhus is visible, and I believe none 

 exists ; it carries a strong red-brown suboval testaceous oper- 

 culum, sharp above, rounded below and at the outer edge, and 

 straighter on the columellar side. The structure of the fine 

 striae on the upper surface is of subannular figure, with a longi- 



