THE NAUTILUS. 131 



Volutilithes muricina is evidently well removed from the forms 

 usually described as Volutilithes splnosus and Volutilithes petrosus. 

 The use of the generic name Plejona to designate such forms as the 

 the latter, seems, however, to be without warrant. As Mr. Newton 

 has pointed out, Bolten refers his Plejona fossilis to four figures in 

 d'Argenville. These four figures represent not only four different 

 species, but four different genera! 



The very existence of the name Plejona rests, therefore, on a poor 

 basis, and it is hard to see how its type P. fossilis, can be restricted 

 to V. spinosa. 



But to return to the application of Plejona to American Eocene 

 forms, the study 1 of very large and carefully collected series from our 

 Gulf States has convinced the reviewer that the forms described as 

 Athleta tuomeyi by Conrad are nothing but races of his Voluta petrosa 

 which have been subjected to an unfavorable environment. They 

 are of one genetic stock, and the differences can in no sense be regarded 

 as generic; in fact they are not even specific. 



M. Cossmann * in reviewing this study pointed out that if its re- 

 sults are to be accepted, Athleta must be substituted for Volutilithes 

 Swainson (1840 non 1831). 



Athleta rarispina is the type of Athleta and is probably related to 

 Lamarck's Voluta spinosa in about the same way that A. tuomeyi is 

 related to Conrad's Voluta petrosa. With our present knowledge it 

 seems better to adopt Athleta for Conrad's Voluta petrosa, its varia- 

 tions, mutations and allies, than to revive Plejona. 



In conclusion it is noted with regret that Dr. Dall has not pro- 

 vided this interesting and important paper with figures, which would 

 have been of the greatest assistance to workers having only small 

 collections or small libraries at their command. BURNETT SMITH. 



FOSSIL MOLLUSCA FROM THE JOHN DAT AND MASCALL BEDS 



OF OREGON (Univ. of California Publications, Bull. Dept. of Geol- 

 ogy, V, no. 3, pp. 67-70). By Robert E. C. Stearns. The new 

 species are Epiphragmophora dubiosa, Pyramidula lecontei and Lym- 

 ncea maxima. The first is apparently related to fidelis or mormorum ; 



'Smith, Burnett: " Phytogeny of the Races of Volutilithes petrosus." Proc. 

 Acad. Nat. Sci., Phila., May, 1906, p. 52. 



* Revue Critique de Pateozoologie, p. 222, October, 1906. 



