Descriptions <>J 'Species, 37 



marking they correspond to the N. aiidineims of Roeiner, origi- 

 nally collected from the Caprina limestone near Austin. 



The Nerineas do not occur in the Comanche series higher than 

 the Caprina limestone of the Frederickshurg Division and not at 

 all in the Upper Cretaceous, where Roemer erroneously supposed 

 this species (originally collected by Mr. Stolley) to occur. 



Neritina sp. indet. 



A characteristic fossil of the beds at the base of the Glen Rose 

 subdivision is a small Neritina. Unfortunately the writer's speci- 

 mens were lost in the removal of his collections to Washington, 

 but there are others in the United States National Museum, 

 which he collected from Hood county for the United States Geo- 

 logical Survey in 1886, and it is hoped that they will be figured 

 and described. 



This form occurs throughout the basement beds in Arkansas 

 and in Hood and Parker counties, Texas. 



Neumayria walcotti Hill. 

 Plate VIII, Figs. 1, 2, 3. 



Ammonites walcotti Hill (not Sowerby). Annual Report Ge- 

 ological Survey of Arkansas 1888, vol. n, p. 139, plate i, figs. 1, 

 la,16. 



Nikitin (Mem. de 1'Acad. St. Petersburg, 1881), defines this 

 genus as follows : 



Shell flat, widely umbilicate; convolutions thinly rounded, 

 marked by fine falcate lines ; lobes and saddles low, slightly 

 incised ; siphonal lobes longer than the first laterals ; the two 

 lateral and accessory lobes little developed. 



Only one specimen of this species has thus far been discovered. 

 It occurred in association with 0. franklini, Vycaria lujani, 

 Ed phyla, arkansaen#i8j and other mollusks herein described. 

 The form very much resembles in outward appearance the fig- 

 ures of the genus Oxynotic^ras of Hyatt, as given by Zittel 

 and Steinmaii in their Manuals, but Professor Hyatt refers to it 

 to Xcu.iiuttjria, and contributes the following comments upon the 

 specimen : 



11 Your Ammonites walcotti is probably a Neumayria. The as-' 

 pect is Jurassic, but this group, Upper Jura, and the species 



