138 



ANNALS SEW YORK ACADEMY OF SCIENCES 



Bellerophon crassus var. wewokanus var. nov. 



The fossils under consideration are all of small size. They can be de- 

 scribed most advantageously by comparing them with Bellerophon crassus, to 

 which they are clearly very closely related. For this purpose, it will be best 

 to use the figures and description given by Meek and Worthen, not only be- 

 cause they are the authentic ones, but because although B. crassus has ap- 

 peared in the literature not infrequently, the citations have seldom been based 

 on the observation of good and characteristic specimens. The most essential 

 difference shown by the Wewoka specimens is that the umbilicus instead of 

 being partly open, is so solidly closed that there must have been a continuous 

 imperforate columella. The size is very much smaller; the shape of the aper- 

 ture more transverse, and the band possibly more elevated. 



It may be that these differences are due to stage of growth, but shells 

 which I am referring to B. crassus as representing a young condition are 

 quite different. From these the Wewoka fossils differ in the following 

 particulars. The volutions are relatively narrower; the slit band is 

 broader and more prominent; the umbilici are more completely closed; 

 the sculpture, instead of consisting of rather regular, transverse imbrica- 

 tions, is made up of fine, incremental lines which, at irregular intervals, 

 become fasiculate, forming small angular costse or incipient plications. 



I may add that the fissure as shown on one of the Wewoka specimens 

 is rather deep, but I am not sure that this feature may not have been ex- 

 aggerated by erosion of the projecting band. Furthermore, on the best 

 specimens, the callosity of the inner lip appears to be imperfectly de- 

 veloped. 



It is possible that this may prove to be the same as B. incomptus, but 

 after comparing my specimens with Gurley's types, which I have had the 

 privilege of examining, thanks to the courtesy of the Walker Museum of 

 Chicago University, I am disposed to think that they are different. The 

 differences appear to me to be those already mentioned as existing between 

 the var. weiroVanus and young B. crassus. 



Horizon and locality : Wewoka formation ; Wewoka quadrangle, Coal- 

 gate quadrangle, Okla. 



Pharkidonotus subgen. nov. 



The very extensive and varied series of shells which in the course of time 

 had been grouped under Montfort's genus Bellerophon have of recent years 

 been distributed among a number of genera and subgenera. Waagen has very* 

 properly restricted the genus Bellerophon to types having a rather narrow, 

 well-developed slit band, moderately deep fissure, a strong callosity on the 

 inner lip. and sculpture consisting only of more or less strong growth lines.s 



8 W. Waasen. Oeol. Surv. India, Mem., Ser. 13, Salt Range Foss.. vol. 1. p. 130. 1887. 



