TURRITELLA. 



Plate I. 



Genus TUEEITELLA. LuMorck. 



Testa elongato-turrita, lanceolato-acuminata, nunquam uni- 

 bilicata, anfractibus mimerosis, smpissinie transversim 

 coslatis vel siriatis, nunquam longitudiaaliter exscnlptis, 

 evaricosis, nunquam spinosis aut muricatis ; apertnrd 

 parviuscidd, plus mlnusve rotimdatd, marginibus dis- 

 jundis, labro sape medio sinuato. 

 Shell eloiigately turreted, laiiceolately acuminated, never 

 umbilicated, whorls numerous, mostly transversely 

 ribbed or striated, never longitudinally sculptured, 

 destitute of varices, never spined or prickly ; apertui-e 

 rather small, more or less rounded, margins disjoined, 

 lip often sinuated in the middle. 

 The genus Turritella afibrds excellent characters for the 

 distinction of species. Constructed upon the simple type 

 of an enlarging tube, the shell is developed with geometri- 

 cal symmetry in short convolutions, varying froin fifteen to 

 thu'ty in number, the same number in each species, 

 forming a sharply acuminated screw. The whorls are 

 sometimes flattened or a little concave, and being always 

 contiguous there is no indication of any umbilicus. No 

 varices or tubercles are formed, as in Cerithium, nor is 

 there any periodical developement of sculpture on the 

 margin of the aperture. The ribs and striae of Turritella 

 range transversely, that is, spirally, never longitudinally, 

 and are rarely granulated or noduled. The best characters 

 for the discrimination of species reside in the first eight or 

 ten whorls from the apex ; beyond this point the sculpture 

 varies slightly or becomes obsolete, as the shell approaches 

 maturity. In colour the reverse of this condition is pre- 

 sented, the pattern becoming gradually darker and more 

 defined towards the aperture, 



The genus Turritella has been somewhat neglected by 

 conehologists. Only eleven species were described by 

 Lamarck, and a monograph lately published in Paris by 

 M. Kiener includes less than half the number now before 

 me from the cabinets of Mr. Cuming, Mr. Metcalfe, 

 Jlr. Hanley, Sir. Edward Belcher, the British Museum, and 

 the Banksian Collection in the museum of the Linnsean 

 Society; amounting to sixty-five all distinctly charac- 

 terized in respect of form, sculpture, and painting. 



The LinuEean species have not been correctly inter- 

 preted by Lamarck, Deshayes, or Kiener, for want of access 

 to the original types of the ' Systema Nature ' preserved 

 in the museum of the Linnsan Society of London. The 

 Turbo acutangulus of Linn.-Bus proves to be a simple 

 variety of the T. duplicat/is, and not the shell assigned to 

 it by M. Deshayes. The shell descrilied as Turbo variega- 

 tm in the 'Systema Nature,' though diflcring materially in 



May, 



general aspect from that which served for the description 

 of the Turbo iuibricaltis, may, nevertheless, be traced to 

 belong to the same species; and the Turbo ungulinus of 

 Linnajus proves to be identical with Lamarck's Turritella 

 fuscata. The British species Turbo terebra, Linn, in 

 'Fauna Suecica' (not of Syst. Nat.) and Montagu, nui^^t 

 be referred to the T. cornea of Lamarck, 



The Turritella brevialis of Lamarck {LeMesal of Adaiison J 

 constitutes the type of a new genus, founded by Mr. Gray, 

 under the name Mesalia, to which I venture to add the 

 Turritella lactea of Moller, and a very characteristic species 

 from the Cumingian collection. A genus has been also intro- 

 duced by Mr. Gray, with equal judgment, under the name 

 Eglisia, founded on the Turritella spirata of the Tanker- 

 ville Catalogue ; and to this is added a species collected 

 by Ml-. Cuming at one of the Philippine Islands. 



The Turritella have a wide range of habitation and dwell 

 at a considerable depth as well as near the surface. The 

 T. cornea has been recently dredged ofiT the Shetland Islands 

 by Mr. M'Andrew at a depth of many fathoms, beyond the 

 influence of light and colourless. Only two comparatively 

 small species besides this, extend so far from north of the 

 equator as the Mediterranean. The greater number are 

 from the Eastern Seas and the shores of Central America, 

 and there are a few known from New Zealand, Australia, 

 and Van Pieman's Land. 



Species 1. (Mus. Cuming.) 

 Turritella ingulina. Turr. testd acmniiiato-turritti, 

 anfractibus quindecim, convexis, lavibus, regidariler 

 decem-striati-s, interslitiis superficialiter sulcatis, aper- 

 turd suboblongo-ovali ; castaneo-rufd, aperturam versus 

 ustulato-iiigrd. 

 The nail-bkuised Turritella. Shell acuminately 

 turreted, whorls fifteen in number, convex, smooth, 

 regularly ten striated, interstices superficially grooved, 

 apertm-e rather oblong-oval; chestnut -red, burnt 

 black towards the aperture. 

 Turbo ungulinus, LinuKus, Syst. Nat. (12th. edit.) p. liUK 



Turritella fuscata, Lamarck. 

 Hab. Senegal, Mouth of the Gambia, West Africa. 



The original specimen which served Linnseus for the 

 type of his Turbo ungulinus, still preserved in the 

 museum of the Linnaeau Society of Loudon, proves, as 

 5Ir. Hanley first pointed out to me, to be Lamarck's T. 

 fuscata. The locality " Seas of Europe " erroneously given 

 in the ' Systema Naturae ' led Dr. Pulteney, and recently 

 M. Deshayes, to assign the Linnaean species to the only 

 Turritella existing north of the Mediterranean ; uii the 



1849. 



