TURBO. 



TESTA turbinatii, spiralis, solidiuscula, spir^ 

 plerumqiie mediocri, nonnunquam brevissima; 

 aperturafere circulari, peritremate acutiiisculo, 

 basi sub(;fFuso; opereulo extiis testaceo, solido, 

 intus corneo, spirali. 



Thk Genus Turbo in the acceptation of Linneans is indeed 

 a mass of confusion, which has been but slightly reformed 

 by modern writers ; the separation of the genera Tiirritella, 

 Scalaria and Cyclostoma cannot but be approved, and 

 CUmsiha ought never to have formed a part of it, because 

 it does not at all accord with the Linnean definition of the 

 Genus. The four above named genera being cleared off, 

 we still find in the Lamarckian Genus Turbo a combination 

 of shells of very various character; we think indeed that 

 the four Lamarckian genera Trochus, Turbo, Monodonta 

 and Delphinula require a careful revision, and we are 

 further of opinion that the confusion at present existing 

 in these genera has principally been caused by too great 

 a dependance having been placed on the external form as 

 a generic character. We shall endeavour to effect such a 

 reformation as appears to us desirable in these four genera, 

 by omitting entirely Lamarck's Monodonta and adopting 

 the following as the distinguishing characters of the other 

 three; and by the further separation of a rather numerous 

 family under the already adopted name of Littorina, We 

 would then, in the first place, separate all those shells 

 hitherto spread into Trochus, Turbo and Monodonta, which 

 have a solid testaceous operculum, whatever may be their 

 external form, under the appellation of Turbo. Our 

 Genus Trochus would consist of such other shells separated 

 from the above named Lamarckian genera as are distin- 

 guished by a spiral horny operculum, with numerous closely 



