52 PHYLOGENY OF FUSUS AND ITS ALLIES. 



F. Spectrum may be a coins type of this series. 



Another specimen labeled F . longissimns has carried the develop- 

 ment a volution further (17364 Haines). The knobs become faint 

 and the aperture is gerontic. 



Localities: Port Jackson, Australia (Nat. Mus. 91743, 16625a?) ; 

 Tasmania (Nat. Mus. 124169, 125169, 91744; M. C. Z. 901). 



The relations of the species of this series may be expressed as 

 follows : 



F. dupetit-thoiiarsii irregularis. F. meyeri. F. dupetit-thouarsii aplicatus. 



F. dupetit-thouarsii. 



F. spectrum. F. dupetit-thouarsii nodosiis. F. amhustus. 



F. novcB-hollandice. 



8. THE FUSUS LONGIROSTRIS SERIES. 



The shells here classed together all belong to the Pliocene of Italy, 

 where they are associated with the species of the F. rostratns series, 

 with which they appear to be genetically related. 



FUSUS LONGIROSTRIS (Brocchi). 



(Plate VI, figs. 1-3.) 

 1814. Murex longiroster Brocchi, Conch. Foss. Subap., vol. 2, p. 418, tav. 8, fig. 7. 

 1856. Fusus longirostris Hornes, Foss. Moll. Tert. Wien, p. 293, pi. 32, figs. 6-7 



(with bibliography). 



The protoconch of this species (pi. XVII, fig. 2 and 3) is unusually 

 accelerated, consisting of at least two complete volutions, the second 

 one with fine riblets throughout. In some specimens, however, the 

 protoconch appears to be of the normal type. No indications of spirals 

 on the protoconch have been noticed, but most of the specimens were 

 so poorly preserved as to leave this point unsettled. 



The conch begins with round whorls which are furnished with 

 round ribs and with spirals. These rounded-whorls continue for two 

 or three volutions, though in accelerated individuals like specimen, fig. 

 I, pi. VI, this stage is reduced to less than one volution, or may be 

 dropped out altogether. Early during the round-whorled (turriculus) 

 stage two spirals become strong on the center of the whorls, causing 

 a bicarination. This is in all respects similar to the bicarinate stage 

 of F. dupetit-thouarsii. 



In the next succeeding stage the shoulder becomes flattened, while 

 the spirals remain faint with the exception of one on the shoulder. 

 The shoulder spiral nearest the peripheral carinse becomes strengthened, 

 so as to change the bicarinate into a tricarinate peripheral angulation. 



