392 HETEKOPHKOSYNID^E. 



Exmouth, June 26, 1853. 



It is stated in a paper of mine on the Rissoa in tlie 'Annals,' 

 vol. x. p. 262, N.S., "that the R. rubra is very common alive 

 in certain localities/' and that " I have never seen the animal, 

 and can scarcely believe it to be a true Rissoa, as the semi- 

 testaceous operculum and its apophysis are more like those of 

 a Chemnitzia." 



This view is corroborated by the reception this day, by 

 favour of Mr. Barlee, of many lively specimens, sent from 

 Penzance in a bottle of sea-water by post, which has enabled 

 me to take notes of all the organs. I am not aware that this 

 curious, I may almost say, anomalous species, has ever been 

 mentioned, beyond a very slight notice by one or two authors, 

 which in most respects 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 ulvae. 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 principal peculiarities of 

 the animal. I think malacologists will be glad of a somewhat 

 enlarged description. 



B. RUBRA, Adams. 

 Rissoa rubra, Adams. 



, Brit. Moll. iii. p. 120, pi. 78. f. 4, 5, & pi. 80. f. 3. 



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

 wrinkled, of 4J to 5J tumid volutions, which form a rapidly 

 increasing cone. Aperture oval, entire, contracted above, 

 rounded basally ; outer margin sharp, without the callous pad 

 of the Rissoa. Axis Tirth, diameter -^th 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 Rissoa. Rostrum very short, not 

 corrugated nor capable of much extension, brindled above 

 with dark smoke-coloured, fine, irregular, close-set lines, 

 below pale yellow ; buccal disk of the same colour, of small 



