221 
Cat. Moll. de Corse, p. 159, pl. 8, £. 4 to 6; also Conch. Icon. 
Rve. Buec., f. 44; Man. of Conch. Tryon, Cantharus, vol. IIL, 
p. 158, pl. 73, £. 266. Variety C. adcocki approaches this ; but 
from the description, which is meagre, and from the plate, one 
would judge that the cost of the foreign shell are less numerous 
and more valid, the canal is less oblique, while the ornament, 
beautifully variegated with black and yellow, is different. 
Triton (Argobuccinum) mimeticus, Vate (Sipho). 
Pl. vi., figs. 6, 6a, 6b. 
This shell was referred to by me in a previous paper as Triton 
mameticus, Tate, and I place it now in the subgenus Argobuccinwm. 
I obtained a living specimen in 20 fathoms off Newland Head, 
and a recent dead one in 17 fathoms off Porpoise Head, both 
places just outside Backstairs Passage, as well as a dead speci- 
men, and fragments of two more. ‘The first two have each three 
varices, and of these the first lies close behind the third. The 
canal figured in Proc. Roy. Soc., 8.A., 1895, vol. XIX, pl. ii, £ 
4, 4a, was fractured. In a living shell 25 mm. in length, with an 
aperture of 8:5 mm. long, the canal is 8:75 mm. in length. Nearly 
closed at first, it gradually becomes about twice as widely open 
at the anterior as at the posterior end; the whole canal is slightly 
uniformly recurved. There is no periostracum. Above the row 
of tubercles the shell is fulvus brown, with deeper-tinted 
blotches; the tubercles are white. Below these it is fulvous- 
brown, except for a spiral white band about two lines in width, 
bounded above and below by a fine line articulated white and 
brown, the joints being rather long, the lower one on the obsolete 
carina, A third articulated line is at an equal distance in front, 
The anterior extremity of the canal becomes gradually deep 
brown. On the outside of the outer lip are four equidistant, 
rather large squarish brown spots. Operculum large, filling the 
aperture, ovate, nucleus apical. The dentition (Pl. vi., fig. 6b) 
shows a central rachidian tooth five-cusped, an inner uncinus or 
lateral six or seven pointed, and two simple uncini, the inner 
sickle-shaped, the outer scimitar-shaped. The disposition of the 
varices is that of Ranella and Argobuccinum, and the peculiar 
flat shape of the shell brings it into alliance with these. The 
simplicity of the uncini, their freedom from Saw-points, suggests 
relation with Ranella rather than J'riton. But the length of the 
anterior canal compared with that of the aperture, which it fully 
equals, is found in Prifon, but is an unknown character in 
Fanella. The only Ranelliform shell in which the canal approaches 
the aperture in 
length is Argobuccinum gigantea, Lam., and no 
Ranella is known to me in which, as in this, the canal equals one- 
third of the total length of the shell. The apical nucleus of the 
