PHVLOGENY OF FUSUS AND ITS ALLIES. 25 



adult characteristics. Accompanying this is a loosening of the inner 

 lip, which often becomes quite separated from the columella. A 

 strong posterior canal is also frequently developed by an encroach- 

 ment of the final portion of the last whorl on that preceding it. 



This species and F. iiibcrculatus have many characters in common, 

 indeed there are intermediate individuals connecting them. Never- 

 theless they are distinct species, representing the same stage of develop- 

 ment in species apparently belonging to separate series. That they are 

 genetically related can not be doubted, in fact they may be regarded 

 as representing the two series at the point of divergence. The slender 

 character of this shell, its smaller angle of divergence and the some- 

 what greater obliquity of the whorls distinguish this species from 

 F, tnherculatus and at once suggest its relation to F. coins. The 

 coloration of the present species consists chiefly in dark brown spots 

 in the intertubercular spaces, these occasionally appearing in the spaces 

 between the ribs, on the turricidus stage. 



Localities: East Indies (M. C. Z. 937, B. S. 219 and 262, Nat. Mus. 

 7378, 36720 and 36718) ; Ceylon (Nat. Mus. 91741, 131157) ; Pacific 

 islands (Nat. Mus. 18379, Phil- Acad.?) ; Mauritius (M. C. Z. 884) ; 

 Tongatabue (Nat. Mus. 7378) (Nat. Mus. 2713). 



FUSUS COLUS (Linne). 



(Plate II, figs. 8-11.) 



1767. Murcx coins Linne^ Syst. Nat. ed., 12, p. 1221. 



1817. Fusiis coins Schumacher, Essai d'un nouveau syst. d. habit, des vers 



Testaces. 

 1842. Fusus coins Kiener, Iconographie, pi. IV, fig. i. 

 1847. Fnsus colus Lamarck, Hist. An. sans Vert. (Desh. Ed.), p. 443. 

 1847. Fnsus cuius Reeve, Iconica, sp. 11. 



The protoconch of this species has been observed in only one speci- 

 men, all the others being imperfect. In that specimen it partakes of 

 the brown color of the other apical whorls, but is perfectly smooth 

 for the first volution. The remaining half volution of the protoconch 

 is ornamented by fine smooth vertical rib'.ets, about fifteen in number. 

 The protoconch ends abruptly with a strong varix. 



The conch begins with a tiirriculiis stage, consisting of six or seven 

 whorls which are round and furnished with regular rounded and 

 spirally sculptured ribs. In rare cases there are more than seven 

 turricnliis whorls. Intercalated spirals appear in the fourth or fifth 

 volution, or in general before the completion of the titniciiliis stage. 



The second stage in the development of the conch is the torcumns 

 sta!.;e, in which the characters are those of an adult F. torcnmiis. This 

 stage appears gradually, being heralded by the appearance of a peri- 

 pheral angulation, which, becoming more and more pronounced, finally 



