TURBO. TRACHELIPODA. 45 
Turritella proto. Plate V. fig. 338. Found in the 
Tertiary deposits, and is characteristic of the Miocene 
strata of Lyell. 
Most of the Turritellz are externally striate, or ridged, and the base of the 
volutions in some have a carinated ridge. The sinus on the outer lip is not so 
apparent in many specimens, as the lip isso seldom met with entire; but if 
the direction of the lines of growth are carefully examined, its existence will 
at once be recognized ; the lower part of the lip is more produced in propor- 
tion as the depth of sinus increases. 
This genus consists of many species, which are found in the seas of almost 
all quarters of the globe. 
The Fossil Turritellz are numerous, they occur in the London Clay, Green- 
sand, and in almost all the strata of the newer formations, namely, Barton, 
Hordwell, Bordeaux, and Grignon. 
Genus XLI. — TUBA. — Lea, 
Generic Character. — Shell oblong, turbinate ; body and 
spire nearly of equal length, and acute; aperture subovate, 
slightly contracted, both above and below. 
Tuba striata. Plate 1V. fig. 42. Found in the Tertiary 
formations of Pennsylvania, North America. 
Genus XLII. — TURBO. — Linneus., 
Generic Character. — Shell turbinated, spiral, solid; spire 
most commonly of mediocre length, sometimes very short ; 
aperture nearly circular, but sometimes a little transverse, 
and slightly trapizoidal ; outer lip acute, but not reflected, 
and subeffuse at the base; operculum solid, testaceous. 
covered internally with a spiral horny plate, which is 
extremely variable in its aspect. 
Turbo Tiara. Plate V. fig. 10. TZ.conicus. Plate IV. 
fig. 39,40. The former from the Mountain Limestone at 
Preston, and the latter from the Greensand of Blackdown. 
The Turbines are liable to much variety of shape, sometimes being Trochi- 
form, at others conical, with a greatly flattened base, and a carinated margin. 
All those shells which are provided with a thick testaceous operculum are the 
only true Turbines, which renders it necessary to withdraw some of Lamarck’s 
Trochi, and Monadontz, and to place them in the genus Turbo. The side 
of the thick testaceous operculum in the Turbines, on which is impressed the 
spiral line, is that side which is attached to the foot of the animal inhabitant, 
while in the thin horny opercules of the Trochi, the line is external, or con- 
trary to those of the genus Turbo. 
The species of this genus are oceanic shells, inhabiting the warmer seas of 
the globe. They are abundant in the Mediterranean, India, and New Hol- 
land. 
Fossil species are rare, and are confined to the newer formations. 
