328 *• Gasteropoda. MOLLUSCA. Proboscidifeka. 
shell, and almost entirely conceals it from view. Being 
smooth and provided with a slimy mucous secretion, 
it thus covers the surface of the shell with a fine layer 
of briglit enamel. Some species possess an operculum, 
but others have none. 
Genus Harpa. — The Harp shells are well known 
to collectors, and are favourite objects of their research; 
the richness of their colours, and the elegance of their 
forms causing them to be much sought after. They 
are swollen ventricose shells, with an ample mouth 
and a short spire. They are all distinguishable at first 
sight by a number of elegant longitudinal ribs, and a 
liigbly-polished callosity on the front part of the colu- 
mella. At present nine species have been described, 
but at the time of Linnaeus only one was known, which 
he described as a species of Buccinum {B. harpa). The 
animal which inhabits the shell was not known even 
to Lamarck, when he founded the genus Harpa. M. 
Baynaud, however, a surgeon in the French navy, was 
enabled to give some details of a species found by him 
alive in India, and his observations were afterwards 
confirmed by MM. Quoy and Gaimard. It resembles 
that of the Olive shells, having a very large foot, which 
is divided into two portions. The anterior half is 
broad, but the posterior portion is elongate, terminates 
in a sharp point, and is nearly as long as the whole 
shell. It is so disproportionately large indeed, that it 
cannot be quickly withdrawn within the shell. The 
animal, therefore, has the power, when suddenly at- 
tacked by an enemy, of spontaneously detaching this 
hinder portion, by pressing it firmly against the lip of 
the shell, or by means of a sudden contraction, and 
thus enabling it to withdraw the rest of its body within 
the shell. It possesses the faculty also of reproducing 
the lost portion after a time. There is^no opercu- 
lum, as such an appendage would be of no use to the 
animal, since it would be separated by the rupture of 
the foot. 
THE SWOLLEN HARP {Harpa vcntricosa) “ glories 
in a rich vermilion red skin.” At the Mauritius it is 
caught, like the Olives, with lines baited with small 
pieces of flesh. “ It is the amusement of the place,” 
Fig. 215. 
The Many-ribbed Harp (Harpa imperialis). 
says Mr. Broderip, “ to watch over the trim apparatus 
of lines hung over some sandbank to tempt the various 
brilliant species of Oliva which there abound, or to 
wait for the more rare approach of the Harp shell, till 
the rich hues of its inhabitant are seen glowing through 
the elear blue water, in tbe rays of a tropical rising 
sun.” 
THE MANY-RIBBED HARP {Harpa imperialis) is 
one of the rarest and most beautiful, and perhaps the 
most precious of all the species. Though now much 
depressed in value, it was at one time a shell of high 
price — fig. 215. 
Placed here by Dr. Gray, comes a small family of 
molluscs, very unlike any of the preceding, as far as 
the shell is concerned, but brought amongst the Probos- 
cidifera, by the structure of the teeth and the form of 
the animal. 
Family — LAMELLARHD.®. 
This family have a thin, pellucid, spiral, ear-shaped 
shell, with a large patulous aperture, and a receding 
inner lip. The mantle is large, and completely ccTv'ers 
the shell ; the proboscis is elongate, strong, and retrac- 
tile ; and the tongue is linear, and spirally twisted 
behind, as in Purpura. The familj' is represented in 
Plate 1, figs. 1-4, by the species Ermea perspicua, 
which is a native of Great Britain, and fig. 5, Cm'iocella 
nigra. 
Family— FASCIOLARHD^. 
This family contains the Tulip shells and the Mitres. 
Genus Fasciolaria. — The Tulip shells are fusi- 
form, elongated, and swollen, with a conical spire. The 
whirls are round and smooth, or angular and waved ; 
the mouth is ovate, outer lip crenated, grooved within ; 
columella tortuous with several oblique folds in front. 
The canal of the shell is elongate, and the operculum 
claw-shaped, with the nucleus apical, sometimes radiately 
grooved. The species are not numerous, only about 
sixteen having been described ; but they have a wide 
range in their distribution, being found in the Medi- 
terranean, Cape Verd islands, West Indies, Ceylon, 
Philippine islands, Australia, Western Africa, and South 
America. One of the species, the Gigantic Tulip shell 
{Fasciolaria gigantea), from the South Seas, is very 
large, sometimes attaining a length of nearly two feet. 
Genus Mitra. — The Mitres have a fusiform shell 
with a conical, elevated spire, compressed whirls, a 
small mouth, and a short canal. The columella is 
obliquely plaited with about five folds, and the oper- 
culum, when present (it is wanting in the larger species), 
is very small. The mantle of tbe animal is inclosed, 
and the foot is small, folded longitudinally when con- 
tracted. The proboscis is generally very long and 
large, that of Mitra episcopalis being more than one 
and a half times the length of the whole shell, and being 
capable of being projected to the distance of five inches. 
The species are numerous, exceeding three hundred 
and fifty, and varj^ very much in form and sculpture. 
They are found chiefly harbouring in the Philippine 
Archipelago and other groups of islands, few occurring 
on the shores of continents, and in deepwater from fifteen 
to eighty fathoms. When irritated, some of them emit 
a purple fluid having a nauseous odour. The larger 
species are said to be sluggish animals. This seems 
