60 PHYLOGENY OF FUSUS AND ITS ALLIES. 



Figures 9 and 10 illustrate other forms in which the round swollen 

 ribs are strongly developed. These approach closely to the variety 

 bononicnsis Foresti (Cat. Moll. Foss. Plioc. Bolognese, p. 32, tav. i, 

 fig. 10, 11), in which this feature is carried to excess. 



Localities: Italy; Caste41arquato, Luganiano, and Asti (M. C. Z. 

 1448, 1449, 1450, 1451) ; Orciano (M. C. Z. 27805-Pl. VII, fig. 5) ; 

 Palermo (M. C. Z. 27807) ; Stazzano (M. C. Z. 1556) ; Sicily (Desh.) ; 

 France; Touraine (Desh.); Vienna Basin (Homes). 



Horizon: Miocene and Pliocene (?) Subapennine formation, Etage 



27, north Italy. 



FUSUS BREDJE Michelotti. 



(Plate VII, figs. 1-3, Plate XVII, fig. 4) 

 1814. Murex rostratus Brocchi, Conchiologia Foss. Subapen., p. 416, tav. 8, fig. i. 

 1847. Pleurotoma bredce Michelotti, Foss. Mioc. Italic, p. 300, pi. 17, fig. 7. Not 



Fusus bredce, ibid., p. 398, pi. X, fig. 8. 

 1856. Compare F. rostratus Hornes, Foss. Moll. Tert. Beck. Wien, p. 291, p. 



32, fig. I, and F. austriacus Hoernes and Auinget, Cast. Oestreich Ungarn., 



p. 251, pi. 31, fig. 3. Not F. bredcE Hornes, Foss. Moll. Tert. Beck. Wien, p. 



284, pi. 31, fig. I. 

 1872. Fusus hreda Bellardi, Moll. Terr. Terz., pt. i, p. 128, pi. IX, fig. i, ib. 



This species represents an extreme specialization of a type de- 

 scended from F. rostratus. The specialization lies chiefly in an 

 accentuation of features, shown in progressive individuals of F. 

 rostratus, but never very strongly developed. F. bredce is a progressive 

 type which has succeeded in carrying on the line of development begun 

 by a certain section of F. rostratus, but generally abandoned when, 

 with old age, the individual reverted to the more primitive and senescent 

 condition of round whorls with swollen ribs. F. bredcu is an accelerated 

 type when compared with F. rostratus. The features which in the 

 latter species appeared only in the adult are in the former assumed and 

 passed through quite early in life. 



The protoconch is of the normal Fusus type, but somewhat de- 

 pressed. It comprises one and a half volutions and ends with a strong 

 varix. It is smooth except for the last portion of the last whorl, which 

 is marked by narrow faint vertical riblets, which are rather widely 

 separated (pi. XVII, fig. 4). 



The first whorls of the conch are rounded and bear coarse rounded 

 vertical ribs, separated by less than their width, and crossed by closely 

 set rounded spirals. The two central spirals quickly become strength- 

 ened, thus giving the whole an angular character. Intercalation of 

 spirals begins with the fourth volution of the conch. 



The upper one of the two central spirals becomes stronger than the 

 lower one, while at the same time the ribs of the shoulder diminish in 

 strength, and the shoulder itself is flattened. The upper spiral in the 

 adult stage becomes a spinous carina, the spines vertically flattened and 



