310 TROCHID. 
The 7. alabastrum may be a development of the 7. zizi- 
phinus, from climate; it is a Zetland production. 
The T. conulus of Linnzus, Turton, and Donovan is exotic ; 
what passes for it in British collections is usually a slender, 
turreted, elongated variety of T. ziziphinus. 
** Discoidal, subdepressed, umbilicated. 
T. macus, Linnzus et Auct. 
T. magus, Brit. Moll. ii. p. 522, pl. 65. f.6, 7; (animal) pl. D.D. f. 3. 
Animal inhabiting a subdepressed, subturriculated, conical, 
coarsely striated tubercular shell of 5-6 tumid volutions, 
lineated with oblique red-brown lines. Mantle even, except 
that on the right side there is often seen an incomplete 
tubular branchial fold. The head is a short muzzle, finely 
crenated at the upper part of its semicircular termination ; it 
is adorned with two suboval, approximating, large and long 
head-lappets, with white fimbriated fringes at thei edges, 
which often hang over the head; their colour above is pale 
sulphur-yellow, beneath, striated with vivid pink blotches on 
a greenish-yellow ground ; the neck on each side is pale pink ; 
the muzzle, on the upper part, is branded with dark transverse 
ines, and is studded, where the head-lappets do not interfere, 
with five short, thick, distinct white sete ; the buccal disk is 
yellow. The tentacula are long, rounded, basally tumid, sub- 
conical, gradually becoming filiform and pointed ; the ground 
colour is white, rmged more conspicuously on the upper than 
on the under surface with a compound colour of purplish- 
brown. The eyes are of turquoise blue, with black pupils, fixed 
externally on distinct, orange-coloured, tumid pedicles. The 
foot is a broad elongated oval, pamted above with a mixture of 
red-brown and yellow lozenges, arranged in shagreen fashion ; 
the sole is yellow, partially marked anteriorly with an in- 
distinct medial line, and has a fine white marginal fringe; it 
carries a well-expanded operculigerous lobe of the same colours, 
similarly shagreened, ornamented with longer fringe than the 
sole, and mottled with white and brown patches, having at 
the margin, at equal distances, three longish, slender, filiform 
