"56 MOLLUSCA. 



The most common species, Turbo defphimix, L. ; List., 608,. 

 45, takes its name from the ramous and convoluted spines, 

 which have caused it to be 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 Siliquariee, to some cleft \jt 

 the brancliial 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. 



TuRRiTELLA, Lam. 



The same round aperture as in Turbo properly so called, zvA 

 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 (Jurreted'). The eyes of the animal are 

 placed on the exteinal base of its tentacvila ; the foot is smallf . 



They are found in great numbers among fossils ; the Proto, Defr.» 

 shovild'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 whorl ; it 

 is moreover surroiuided by a ridge, Avliich is formed, from space to 

 space, as the shell of the animal increases in size, resembling so 

 many steps. The tentacula and penis of the animal are long and 

 slender. 



One species celebrated for the high price it commands («),the 

 Turbo scalaris, L.; Chemn., IV, clii, 1426, &c. vulg. ScalalOr 

 is distinguished by the whorls only coming in contact at the 

 points Avhere the ribs \inite them, the intervals being open. 



A second species, the Turbo clalhrus, 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 subgenera, in which the aperture 



is entire, rovmd, or nearly so. and operculated, may be placed here. 



Of this nmnber is the 



* Add, turbo nodulosus, Chemn., V, clxxiv, 1723 — 24; — T. curinatus, Born., 

 XIII, 3 — 4 ; — Argonauta, coniu, Fichtel and Moll., Test. Micros., I, a, e, or Liy- 

 PISTE, Montf. 



f Turbo imbricafus, Martini, IV, clii, 1422 ; — T. rejMcutus, Il>., cli, 1412; Listi.» 

 590, 55 ; — T. actifamjuhis, List., 591, 59 ; — T. dvpHcutus, Martini, IV, cli, 1414 : — 

 T. exoktus, List., 591, 58; — T. ferehni, Id., .590, 54; — '/. variegatvs, Martini, IV. 

 clii, 1423; — T. obsoktus, Born., XIII, 7- 



{^ («) Tliis is the Wentletrap of the collectors. We remember sccingr one iu 

 Bullock's Museum, which was valued at 200 pruineas, and also four specimens were 

 sold at one sale, which brought from £ i 6 to £20. — Exg. Ed- 



