RISSOA. 19 



9. R. ABYssi'coLA"^, Forbes. 



R. abyssicola, F. & H. iii. p. 86, pi. Ixxviii. f. 1. 2, and (animal) pi. JJ. 

 f. 3. 



Body whitish, with a faint tinge of yellow or saffron on the 

 front, and microscopically speckled with flake-white : inantle 

 rather thick- edged; pallial processes one on each side, short and 

 not protruded beyond the mouth of the shell ; snout small and 

 narrow, deeply cloven, carried somewhat in advance of the 

 foot: tentacles thread-shaped, flattened, clothed with minute 

 and short but not numerous cilia : eyes large and black, on 

 bulbs at the lower base of the tentacles : foot squarish in front, 

 with short angular corners, narrowing behind to a rounded and 

 slightly bilobed tail : ap'pendage single, placed far behind the 

 tail, and issuing from the opercular lobe. 



Shell oval, with a slight tendency to oblong and a somewhat 

 oblique outline, rather solid, semitransparent and glossy; 

 scidpture, numerous slight longitudinal ribs on the last three 

 or four whorls, but not extending to the base ; they are flex- 

 uous on the body- whorl and curved on the others ; the labial 

 rib is strong, and placed close to the mouth ; the whole surface 

 is covered with close-set and fine, apparently (but not really) 

 undulating spiral striae, which are as prominent although not 

 so large as the ribs, and by their intersection give a some- 

 what muricated appearance ; these striae cross the labial rib, 

 as in the preceding species, and reach to the outer lip ; the in- 

 terstices of the striae on the base show, under a high magnifying 

 power, indistinct traces of longitudinal ribs; the uppermost 

 whorls are microscopically reticulated: colour clear-white, 

 with occasionally a blotch of reddish-brown behind the labial 

 rib: spire short and abrupt: whorls 5, somewhat compressed 

 but rounded, the last occupying about two-thirds of the spire, 

 and the first minute and flattened : suture deepish, and some- 

 times slightly channelled : mouth roundish-oval, obliquely ex- 

 panding outwards: outer lip narrow, thin, and sinuous, in- 

 curved above : inner lip reflected on the pillar and at the base, 

 united with the outer lip, but not forming a distinct peristome : 

 operculum filmy, few-whorled, with a small excentric spire, 

 and finely striated in the line of growth ; tlirough it may be 

 seen the opercular lobe, of a yellow colour. L. 0-085. B. 0-05. 



Habitat : Mud in 50-70 f., Loch Fyne (where M'An- 



* Inhabiting deep water. 



