PHYLOGENY OF FUSUS AND ITS ALLIES. 



93 



If we accept the geologic horizon as given for these species.* we 

 have great difficulty in arranging the species in their proper hiologic as 

 well as geologic relation. The following may serve as an attempt : 



Recent. 



H. timessa. 



H. robusia. 



Pliocene. 



H. rob us la. 



JI. barbarensis. 



H. caroUnensis. 

 H. caloosa'cnsis. 



(Intermediate varieties 

 may occur.) 



H. cqualis. 



Miocene. 



H. burnsii. 

 H. exilis. ^1 



Oligocene. 



H. caloosaensis-like 

 ancestral type. 



15. THE GENUS EUTHRIOFUSUS Cossmann. 



This generic name w^as proposed by Cossmann (Paleoconchologie 

 comparee 4me liv., p. 27, Oct., 1901) for Fasciolaria burdigalensis 

 Basterot, a type which had been frequently referred to Piisits. I had 

 previously used the generic name Fusiolaria in manuscript for this 

 species, but Cossmann's name having been published has priority. The 

 following generic diagnosis is new. 



Fusiform shells with condensed spire which approaches that of 

 Fulgiir. The protoconch (pi. XVIII, fig. 16) is turbinate, consisting of 

 about two smooth apical whorls, gradually increasing in size, followed 

 by a whorl or more with strong oblique, slightly concave riblets. It 

 gradually merges into the conch, in which the ribs are vertical and 

 extend from suture to suture. An angulation appears in the first 

 whorl of the conch, outlining a shoulder, which later on becomes con- 

 cave from the development of a posterior canal and a corresponding 

 subsutural band. Spirals numerous, crowded, intercalations appearing 

 in the nepionic whorls. In the neanic whorls the ribs begin to dis- 

 appear and arc found as nodulations only on the periphery of the later 

 whorls in most cases, though they sometimes persist throughout (in 

 retarded species). 



Genotype: Faseiolaria burdigalensis Basterot. 



EUTHRIOFUSUS BURDIGALENSIS (Basterot). 

 (Plate VIII, figs. 1-8, 16, 20, 22; Plate XVIII, fig. 16.) 

 1820. Le Fuseau de Bordeaux De France, Diet. Sci. Nat., T. XVII, p. 541- 

 1825. Fasciolaria burdigalensis Basterot, Mem. Soc. d'hist. Nat. Paris, T. 2, 



p. 66, pi. VII, fig. II. 

 1827. Fasciolaria btirdigalcusis Grateloip, Bull. Soc. Linn. P.ord., T. 11. 



* See Dall, Tabic of Tertiary Horizons. 



