JEFFREYSIA. 389 
ovarium, when present, between the lobes, are very conspi- 
cuous through the tenuity of the shell. 
The animal is not shy; it shows the organs freely and 
marches with vivacity; it also swims and floats with perfect 
ease, as is usually the case with all the smaller and shorter 
Chemnitzie. It has frequently occurred in the quiet half- 
tidal pools at Exmouth. 
? J. OPALINA, nonnull. 
2? J. opalina, Brit. Moll. ii. p. 154, pl. 76. f. 3,4, & iv. p. 267, pl. 133. 
f. 6; (animal) pl. M.M. f. 2. 
J. globularis, Brit. Moll. iv. p. 268, pl. 133. f. 5. 
Live specimens of the beautiful so-called Rissoa opalina 
were received in a bottle of sea-water, from my friend 
Mr. George Barlee, at Falmouth, whose laborious and painful 
journeyings— 
aes aed “per omnes 
Terrasque, tractusque maris,” 
of the wilds of the Ultima Thule and Hebridean seas, have 
enriched science with so many rare and interesting objects ; 
the present one is invaluable, as it clears up several doubtful 
questions which might long have remained unexplained, if 
this curious animal had continued to escape observation. 
Though somewhat torpid, I have observed the organs, an 
account of which, I am sure, will gratify many of my readers. 
There is no recorded description of the animal. 
Animal inhabiting a spiral, smooth, thin, white, subglobose 
shell of three volutions. Mantle of the palest azure, slightly 
canaliculated, otherwise even with the shell. The head is a 
rounded, short, contractile, proboscidiform muzzle, which is 
rarely carried beyond the foot and tentacula; it is vertically 
cloven at the terminus and under part, and furnished with a 
pair of subcircular jaws and lingual riband, which in several of 
the examples I frequently saw protruded after the manner of 
the Rissoe; the head and neck are brindled with fine dark 
lead-coloured lines. 
There are a pair of tentacula on each side the neck behind 
the muzzle, sprmgmng from a distinct common origin or 
