58 



PHYLOGENY OF FUSUS AND ITS ALLIES. 



This Species bears the same relation to F. clavatus that F. 

 iiKzquicosfatus bears to F. longirostris. Both this species and F. 

 clavatus may be regarded as members of a lateral branch from the 

 radical of the longirostris stock. 



Locality: Asti in Piemont (M. C. Z. 1214) ; Senese (Type in Regie 

 Museo di Firenze). 



Horizon: Subapennine stage (Etage 27), Pliocene. 



The relations of these species may be expressed as follows : 



F. castellarquatensis. 



F. gabbi. 



THE FUSUS ROSTRATUS SERIES. 



This series is represented in the Miocene and Pliocene of the 

 Mediterranean region and by species living in the Mediterranean Sea 

 to-day. The Tertiary representatives show a greater range of varia- 

 tion than do the recent ones, judging from a fairly extensive series of 

 specimens seen and from published figures and descriptions. Several 

 species may be distinguished both among the recent and the fossil 

 forms, the gradation between them being, however, complete. 



Pliocene Species. 



FUSUS ROSTRATUS (Olivi). 



(Plate VII, figs. 4-10.) 

 1792. Murex rostratus Olivi, Zoologia Adriatica, p. 153. 

 1856. Fusus rostratus Hoernes, Foss. Moll. Tert. Becken Wien, p. 290, taf. 32, 



fig. 2 (with synonymy). 

 1871. Fusus rostratus Bellardi, Moll. Terz. Piem., etc., pt. i, p. 129, pi. 9, fig. 2. 



The protoconch of this species is of the normal Fusus type, ending 

 abruptly with a varix. The riblets on the last portion of the proto- 

 conch are narrow and rather far apart, leaving interspaces which are 

 more than twice the width of the ribs. 



The conch begins abruptly with round whorls furnished with strong 

 round ribs which extend from suture to suture, and are crossed and 



