78 PHYLOGENY OF FUSUS AND ITS ALLIES. 



If this Species is not the young of some more highly developed type, 

 it probably represents a scarcely modified successor of the Eocene F. 

 aciculatus (probably the British variety) ; and it may in turn have be- 

 come the ancestor of the American progenitor ( ?) of F. turriculus and 

 F. eucosmius, i. e., F. hennickeni of the Upper Oligocene ( ?) of the 

 West Indies. 



The other "Fusi" from the Oligocene of North Germany belong 

 to other genera. 



FUSUS INCONSTANS Michelin. 



1831. Fusus inconstans Michelin, Mag. de Conchyliologie, p. 3;^, fig. 33. 



This is a Fusoid shell with the earliest whorls plicated, but the last 

 three smooth. The inner border of the lip is Urate, and the canal 

 slightly flexed. A rather strong posterior canal is indicated. 



Horizon and Locality: " Falunieres de Salles pres Bordeaux 

 (Michelin). 



FUSUS PREVOSTI Partsch. 



1856. Fusus prevosti Partsch, Hoernes, Foss. Moll. Tert. Beck. Wien, I, p. 285, 

 pi. 31, fig. 9. 



This species, found at Baden, Voslau Steinabrunn and other 

 localities in the Vienna Basin, may be a ture Fiisiis, but its relations 

 are not readily determinable from an inspection of the figure and from 

 the description. Homes compares it with F. longissiuins, to which 

 his figure has some resemblance. R. Hoernes and Auinger (Gast. 

 Oestreich Ungarn, p. 253, pi. 31, fig. i) state that the figure and de- 

 scription are incorrect and give figures of a form with much shorter 

 anterior canal. This makes this shell less like a true Fiistis, and more 

 like a Fasciolaria, to which genus it may belong. 



B. SPECIES OF FUSOID SHELLS GENERALLY 

 REFERRED TO FUSUS. 



12. THE GENUS APTYXIS Troshel. 



(1868. Troschel, Das Gebiss der Schnecken, vol. 2, p. 64.) 

 This genus was founded for the reception of Fusus syracusanus L. 

 It was supposed to differ from the true Fusi in the Fasciolarioid 

 character of the dentition. Typical species of Fusus, however, such 

 as F. inconstans and F. australis, have a very similar dentition. Never- 

 theless F. syracusanus differs sufficiently from typical species of 

 Fusus, to demand a separate generic designation. The most impor- 

 tant points of distinction are the short, slightly sinuous anterior canal, 

 and the long stout spire. The protoconch and early stages appear 

 to be like those of Fusus. 



