SKENEA. 169 



stoma continuum aperturre et pedem animal is antice fila- 

 mentis obsitnm diversa est." 



Since the preceding account of the Littorinida; was 

 written, we have received information respecting the ani- 

 mals of two species, of which the shells only are noticed 

 in the text. 



1. Rissoa costidata. The animal of this species has been 

 observed by Mr. Alder. It has a very broad muzzle, and 

 the posterior filament is the longest of any observed by that 

 gentleman among the British species of Rissoa. In other 

 respects It resembles B. rufilahrum. 



2. Rissoa fulgid a. This curious and beautiful little spe- 

 cies has been taken alive at Exmouth by Mrs. Gulson, a 

 lady to whom our science is much indebted for her zealous 

 and successful pursuit of Malacology. Mr. Clark has 

 forwarded to us a description of the creature drawn up 

 from living specimens communicated by her, and has since 

 sent to us alive and active individuals, which have 

 travelled post to London in a small bottle of sea-water, 

 without any apparent injury to their vitality. We can, 

 from an examination of them, bear testimony to the accu- 

 racy of the following description : — " Mantle of the animal 

 of the palest yellow, even with the shell ; head flat, 

 grooved above and below ; mouth a vertical fissure ; head 

 and neck throughout of a pale sulphur yellow hue. Ten- 

 tacula short, divergent, setose, blunt, stout, hyaline white 

 suffused with intenser minute snowy opake flakes ; eyes large 

 and conspicuous, placed on eminences, but not on adnate 

 offsets at the external bases. Foot mixed hyaline flake- 

 white, not very slender, slightly auricled, with a medial 



VOL. III. z 



