378 Mr. Cosmo Melvill on the 



genera. The above, however, are some of the more leading, 

 common, and conspicuous members of the various groups, 

 and therefore a considerable substratum of knowledge is 

 formed by this valuable aid, armed with which, he who ven- 

 tures on framing a line of sequence may, with some measure 

 of confidence, forge the links of connection here and there, 

 and unite the whole array in a congruous chain. 



I would therefore propose to group the members of this 

 family Fasciolariince thus : — 



I. Fusus (Lamarck). Types F, colus (L.), F. inconstans 

 (Lischke). 



II. Clavella (Swainson), Cyrtuhis (Hinds). Types 

 C. serotina (Hinds). 



III. Fasciolaria (Lam.). Type F. tulipa (Lam.). 

 Subg. Pleiiroploca (Fisch.). Type F. trapezium 



(Lam.). 



IV. Taron (Hutton). Type T. diibius (Hutt). 



V. Buccinofusus (Conrad). 



Boreofusus (Sars.). Type B. Berniciensis (King). 



VI. Latirus (Montfort). Type L. gihbulus (Gmelin). 

 Syn. in "^"axt Aptyxis (Troschel). 

 Do. Leucozonia (Gray). 



VII. Peristemia (Morch). Type/*, nassatula (Lam.). 

 It is with the four last genera we alone have to do 

 at present: the i^//j^' proper and Fasciolarice^ whose dentition 

 is almost identical, may form the subject of a future paper. 

 In both these genera, the denticles of the laterals are larger 

 and far more numerous than in the Latiri. 



It will be noted that the old genus Leucozonia of Gray 

 is dispensed with in this new arrangement. The shells 

 seemed to fall naturally into their places, in the centre of the 

 sequence. The presence of a labial tooth, which is of 

 extreme prominence in L. cingulattcs (Lam.) does not, to 



