56 
MOLLUSCA. 
The most common species, Turbo delphinus, L. ; List., 608, 
45, takes its name from the ramous and convoluted spines, 
which have caused it to he compared to a dried fish*. 
Pleurotoma, Defr. 
Fossil shells with a round aperture, on the external margin of 
which is a narrow incision which ascends considerably; it is proba- 
ble that it corresponded, like that of the Siliquaria?, to some cleft in 
the branchial part of the mantle. 
M. Deshayes already makes upwards of twenty fossil species. 
The ScissuRELL.® of M. d’Orbigny are living species of the same. 
Tcrritella, Lam. 
The same round aperture as in Turbo properly so called, and 
completed, also, by the penultimate whorl; but the shell is thin, and 
is so far from being convoluted in one plane, that its spire is pro- 
longed into an obelisk (^turreJed^, The eyes of the animal are 
placed on the external base of its tentacula ; the foot is smallf. 
They are found in great numbers among fossils ; the Proto, Defr., 
should be approximated to them. 
SCALARIA, Lam. 
Have the spire, as in Turritella, elongated into a point, and the 
aperture, as in Delphinula, completely formed by the last wliorl ; it 
is moreover surrounded by a ridge, Avhich is formed, from space to 
space, as the shell of the animal increases in size, resembling so 
many steps. 'J’he tentacula and penis of the animal are long and 
slender. 
One species celebrated for the high price it commands (a), the 
Turbo scalaris, L. ; Chemn., IV, clii, 1426, &c. vulg. Scalafa, 
is distinguished l)y the whorls only coming in contact at the 
points where the ribs unite tliem, the intervals being open. 
A second species, the Turbo claihru'!, L. ; List., 588, 50, 51, 
is not marked by this peculiarity ; it is more slender, and very 
common in the Mediterranean. 
Some terrestrial or fresh water subgcnera, in Avhich tlie aperture 
is entire, round, or nearly so, and operculated, may be placed here. 
Of this number is the 
* Add, Turbo jwdidosvs, Chemn., V, clxxiv, 1723 — 24; — T. rarinaius, Born., 
XIII, 3 — 4; — Aryonaufa, cornu, Fichtel and Moll., Test. Micros., 1, a, e, or Lip- 
piste, Montf. 
"I- Turbo inibricuius, Martini, IV, elii, 1422; — T. replicalus, Ih., eli, 1412; List., 
590, 55 ; — T. acutunyulus, List., 591, 59 ; — T. duplicatus, Martini, IV, eli, 1414 : — 
T. exoletus, List., 591, 58; — T. tcrebru, Id., 590, 54; — 2\ ritricynius, Martini, IV, 
clii, 1423; — T. obsotefus, Born., XIII, 7. 
(a) This is the Wentletrap of the collectors. We rememher seeing one in 
Bullock’s Museum, which was valued at 200 guineas, and also four specimens were 
sold at one sale, which brought from ^ i 6 to £ 20. — Eng. Ed. 
