RISSOA. 379 
M. Loven would term it, “ dete vibrantes,’ beneath which it is 
slightly constricted, and a little beyond the middle, posteally, 
is fixed on a simple lobe without lateral expansions or terminal 
cirrhal filament; the light yellow suboval operculum with di- 
stinct grossly-spiral turns, exactly as in the paucispiral Litto- 
rinide ; below the operculum the foot is visibly contracted 
on each side, and terminates im a rounded, rather broad point ; 
no median line is apparent in any part of the sole. 
This creature is not at all shy; it remained lively for thirty- 
six hours, and gave every facility for good examination ; it 
readily creeps up the deepest glasses, and however often 
brushed down, starts again with unabated vigour. The speci- 
men described was detected in Littleham Cove, between 
Exmouth and Budleigh Salterton, in the littoral level, in 
debris of minute decayed shells mixed with sand and mud 
that had an offensive odour, the mass being deposited on the 
margins of deep quiet pools affording nutriment to certain 
long, narrow, grassy sea-weeds. I have been thus particular, 
to obviate difficulty to future naturalists, and I wish them 
success in obtaining a live specimen with less trouble than I 
have had. 
The habitat of this species is, I believe, strictly littoral ; its 
associates are the Rissoa parva, R. striata, R. planorbis, nobis, 
(Skenea planorbis, auct.), as these are found in the same mass 
of spoil. 
That this is a Littormidan and almost a strict Rissoidean 
animal, allowing a triflimg margin for specialty-variations, 
admits of no doubt. It has no malacological community with 
Turritella, Achs, or Chemnitzia; but as the muzzle is carried 
in nearly a similar position as in the latter genus, the young 
malacologist must take care in so small an object not to 
be misled by this circumstance, or by the centrality of the 
eyes at the base of the tentacula: the veteran observer with 
delicate and apt manipulation, patience, and good glasses, will 
easily detect the vertically cloven disk and corneous jaws, 
which, with the rissoid simple tentacula, will demonstrate that 
this animal is merely an elongated Rissoa. 
