112 Trans. Acad. Set. of St. Louis. 



side near the suture. It is believed that this specimen repre- 

 sents a distinct species and the name P. depressa is proposed 

 for it. The type specimen has a diameter of 16 mm. and a 

 height of 9 mm., with an umbilicus whose approximate width 

 is 4 mm. 



Phanerotinus paradoxus Win. 



Pi. VII. f. l. 



Shell discoid, with three gradually and regularly expanding 

 volutions disjoined throughout their entire extent, the inner 

 ones depressed below the plane of the outer. Cross-section 

 of the volutions subcircular. Surface marked by faint, trans- 

 verse lines of growth. Diameter of shell, 25 mm., width of 

 the outer volution at the aperture, 8 mm. 



Remarks. The illustration of this specimen published by 

 Hall * is in error in showing the inner volutions in contact, 

 and also in making the transverse lines of growth too strong. 

 It is possible that this shell should be considered as sinstral 

 rather than dextral. If it is a dextral shell, then the depres- 

 sion of the inner volutions is so great that the under side is 

 more nearly in a plane than the upper, while if it be a sin- 

 stral shell the inner volutions are but slightly depressed below 

 the plane of the outer one, and the under side is broadly 

 umbilicate. 



The types of this species are wax casts from a natural 

 mould which has not been seen and which is probably lost, 

 and it is not certain that the species is a member of the Cho- 

 nopectus fauna, as it may belong in the upper ** yellow sand- 

 stone." 



Bellerophon bilabiatus W. & W. 



PI. VI. f. 9-10. 



Shell of medium size, subglobose, narrowly umbilicate; the 

 inner volutions expanding somewhat gradually, the outer 

 volution rather broadly expanded at the aperture. The outer 

 volution with a narrow subangular dorsal band, becoming 

 more prominent and carinate towards the aperture. The 

 outer lip deeply notched, giving the aperture a strongly 



* Pal. N. Y. h\pl.!6.f. 16. 



