EBURNA. TRACHELIPODA. 31 
shell, rather narrow and notched at the base, which is more 
or less emarginate, and ending in a very short canal ; 
columella somewhat contracted in the centre, opposite the 
internal tumour of the outer lip, and denticulated at the 
base ; outer lip thickened and tumid, and denticulate in the 
centre internally; in some species the tumid part is repre- 
sented by a few strong projecting teeth. Said by Adan- 
son to be provided with a small, slender, horny operculum. 
Colombella nebulosa. Plate III. fig. 36. 
The Colombelle inhabit the ocean. Fossil species are found in the Tertiary 
deposits of Italy. 
TRIBE III.— PURPURIFERA. 
Shell with a short canal ascending posteriorly, or pro- 
vided with an oblique notch at the base of its aperture. 
SUBDIVISION I.—Shells with an oblique notch, directed backwards, 
and furnished with a canal. 
Genus XII.— TEREBRA. — Lamarck. 
Generic Character. — Shell greatly elongated, subulate ; 
spire very long, consisting of many flat, gradually tapering 
volutions, terminating in an acute apex; body very small 
in proportion to the spire ; aperture ovate, a little con- 
tracted above, with a short, straight canal at the base; 
columella oblique, spiral, or twisted, frequently striated ; 
outer lip thin and sharp at the edge; provided with a 
thickish, oblong operculum, which is somewhat pointed at 
the base, but not spiral. 
Terebra plicatula. Plate V. fig. 23. 
The shells of this genus and those of Turitilla resemble each other, but are 
easily distinguished by the form of the aperture, which, in the latter genus. 
is nearly circular, and are destitute of a canal, and the twisted columella of 
Terebra. 
The Terebre are oceanic shells, inhabiting principally the seas of Africa, 
India, and the West Indies. They occur fossil in the Newer Strata of Turin, 
Bourdeaux, Piucenza, and in the London Clay. 
It has been proposed by Blainville to form a new genus, under the name of 
Subula, from the more ventricose species, agreeing with Terebra maculata ; 
but this is quite an unnecessary alteration. 
Genus XIII.— EBURNA. — Lamarck. 
Generic Character.— Shell ovate or elongated, with a 
fine polished surface ; outer lip simple; aperture longitu- 
dinal ; emarginate at the base ; columella umbilicated above, 
with a canal below the umbilicus. 
Eburna glabrata. Plate III. fig. 25. Found in the 
