376 
MOLLUSCS. 
of Turbinellidce, the shells are compact and very strong, tuberculous or spiny, 
with short spires, and the anterior canal considerably shorter than in Turbinella. 
The aperture is armed with a few folds on the middle of the columella, and is closed 
by a thick and somewhat twisted operculum. The eight known species are dis¬ 
tributed over the Red Sea, Philippine Islands, Polynesia, Pacific coast of Central 
America, and the West Indies. Fulgur and Melongena both include large striking 
shells from the United States and West Indies; and Sycotypus canaliciilatus, also 
from the States, is remarkable for the deeply channelled suture separating the 
whorls. The egg-capsules are very curious, consisting of a long string of round 
discs, about the size of a shilling, but somewhat thicker, attached to the cord by 
one edge. Each capsule contains a number of eggs, and the young eat their way 
out at a spot opposite the points of attachment. Semifusus colosseus is one of the 
largest living gastropods, attaining a length of about 14 inches. It is an 
inhabitant of the Indian Ocean, and also occurs at the Philippine Islands. Another 
giant is the well-known Fusus proboscidiferus, of which the broadly fusiform shell 
sometimes attains a length of 2 feet. It is found on the west and north-west coast 
of Australia, and on account of the peculiar nucleus of the spire has been placed 
in a separate genus, Megalatractus. The egg-capsules form a cylindrical mass 
marked with a dozen longitudinal equidistant ridges, and divided off into compart¬ 
ments, each compartment containing from twenty to thirty young. When they quit 
the egg-case, they are about an inch in length, and bear no resemblance to the full- 
grown shell. 
The whelks form the characteristic group of the family Buccinidce, which 
also includes a considerable number of other genera, and numerous species. 
The animals usually have a long siphon and a large 
foot, more or less square in front and somewhat pointed 
behind; the head is provided with a pair of tentacles 
which support the eyes on the outside. The lingual 
ribbon is well-developed, with three rows of pronged 
teeth, the central with three to six cusps, the laterals 
two- or three - pronged. The form of the shells is 
variable; some are fusiform, with a distinct anterior 
canal, others ovate, with the canal reduced to a mere 
notch. All are provided with a horny operculum, 
which assumes different forms in the various genera. 
Chrysodomus is essentially a northern or Arctic race, 
and one of the fusiform types with a distinct siphonal canal. C. antiquus, the largest 
of the British marine gastropods, was also common in the English Crags. Reversed 
or sinistra! specimens were the commonest form in the Red Crag. C. contrarius, found 
living on the coast of Spain and Portugal, is a closely allied species. Sipho, Volu- 
topsis, and Jv/tncda are other northern fusiform groups, which have a few British 
representatives. The common whelk {B. undcdum ) is the typical representative of 
the genus Buccinum, and is such a familiar object that a description of the shell is 
needless. We may, however, direct attention to the variations existing in this species, 
these being due to difference of locality, depth, etc. Specimens from deep water 
have much thinner shells than shallow-water forms, and those found on some 
Cl 
& 
ROW OP TEETH FROM THE RADULA 
of (a) Buccinum undatum , ( b) 
Murex erinaceus. 
