144 



PHYLOGENY OF FUSUS AND ITS ALLIES. 



species, though in others only one strong columellar plication occurs. 

 A posterior canal is developed on the aperture. Intercalated spirals 

 appear in the early volutions of the conch. In some specimens inter- 

 calation is triplicate on the body whorl. This species is readily dis- 

 tinguished from the preceding by the fainter spirals and the undu- 

 latory character of the ribs. 



Locality: Paris Basin (M. C. Z. 1134, 1130, 1129, 1128, 1132?, 

 ^777?>) (Acad. Sci. 8035, Cossmann) ; Grignon (M. C. Z. 2yyy2). 



Horizon: Middle Eocene, Calc. Grossier. 



COSMOLITHES LJEVIGATUS (Gmelin). 



(Plate XIII, figs. 8, 9, 11.) 

 1788. Murex Jcevigatus Gmelin, Linn. Syst. Natura, Ed. 13, t. 6, p. 3555, no. 11 1. 

 1824. Fustis Iccvigatus Deshayes, Coq. Foss. Env. Paris, p. 531, pi. 70, figs. 14, 15. 

 1889. Clavilithes IcEvigatus Cossmann, Cat. Coq. Foss. Env. Paris, p. 175. 



This species is closely related to the two preceding ones, from 

 which it is distinguished mainly by the final smooth whorls. The 

 protoconch and nepionic stage are as in the preceding species. The 

 ribs are variously developed in the neanic stage, though they are seldom 

 as strong as are those of the preceding species. In the ephebic 

 whorls the ribs become obsolete. The spire is shorter and the aperture 

 longer than in the preceding species. Lines of growth, crowded and 

 lamellose, occur on the last portion of the body whorl, which is globose. 

 The sutures are but slightly impressed, giving an almost uninter- 

 rupted slope to the spire. On the body whorl the spirals as well as 

 the ribs are obsolete. Columella with a strong and a faint plication. 



Localities: (?) (M. C. Z. 1122) ; Parnes (M. C. Z. 1121, 1123, 

 1126) ; Grignon (M. C. Z. 2'j'jyi). 



Horizon: Eocene, Calcaire Grosiere. 



The relations of the preceding species may be expressed thus : 



Rhopalithes japeti. 



R. noce. 



R. clavelloides. 



R. tuberculoides. 



R. rugoides.- 



R. angulatus. 



C. Icevigatus. 



C. subuniplicatus. 



Cosniolithes uniplicatus. 



Fusus sp. (?) 



