Weller — Kinderlwok Faunal Studies. 179 



revolving striae, give a finely cancellated appearance to the 

 surface. Margin of the peristome nearly straight, or with 

 a gentle backward curvature to the shallow central notch." 



Remarks. The specimen of this species here illustrated, 

 is the largest one of the types, being nearly twice as large as 

 the average representatives of the species. On the internal 

 casts the delicate surface markings cannot be recognized, but 

 they are beautifully shown in the external impressions of the 

 shell. On the casts the only surface irregularities usually 

 recognizable, are the revolving dorsal band and some faint,, 

 irregular, concentric wrinkles of growth. 



Among the specimens indicated as types of this species in 

 the University of Michigan collection, three distinct species 

 are represented. A number of the specimens are good ex- 

 amples of Belleroj)hon bilabiatus, and another has been made 

 the type of a new species, Bucanopsis deflectus.* The 

 specimens which are retained as the types of the species are 

 those which apparently were used as a basis for the original 

 description, and were found in the fauna under consideration. 



Bellerophon sp. undet. 



Pi. XV. f. 28. 



This undetermined species is represented in the collections 

 which have been studied, by a single very imperfect speci- 

 men which is here illustrated. The species is much larger 

 than B. perelegans, and when perfect examples are found, it 

 may prove to be an undescribed species. 



Phanerotinus paradoxus Win. 



Trans. Acad. Sci. St. Louis. 10: 112. pi. VIII. f. 1. 



The types of this species are wax casts from a natural 

 mould which probably has been lost. They are said to be 

 from the " yellow sandstone " at Burlington, but as no other 

 specimens have been seen, it is impossible to determine cer- 

 tainly from which yellow sandstone horizon the types were 

 secured. The species was included provisionally in the Chono- 

 pectus fauna, but in view of the fact that the same species 

 occurs in the vermicular sandstone at North view, Missouri, f 



* Trans. Acad. Sci. St. Louis. 10: 114. 



t Trans. Acad. Sci. St. Louis. 9 : 43. pi. V. f. 6. 



