Logan.] 



The Invertebrates, Niobrara Group. 



481 



Outline Classification of Niobrara Species. 



PROTOZOA. 



Rhizopoda. 



Foraminifera. 

 Yitro-calcarea. 

 Globigerinidae. 

 Textularidae. 



COZLE NTEK ATA. 



Porifera. 

 Spongiee. 



Silicispongiee. 



ECHINODEKMATA. 



Crinoidea. 



Uintacrinidse. 

 Uintacrinus. 



Uintacrinus socialis. 



TEKMES. 



Serpulidse. 

 Serpula. 



Serpula intrica. 

 Serpula tenuicarinata. 



MOLLCSCA. 



Pelecypoda. 

 Ostreidee. 

 Ostrea. 



Ostrea congesta. 

 Ostrea larva. 

 Aviculidse. 



Inoceramus. 



Inoceramus flaccidas. 

 Inoceramus deformis. 



Inoceramus. 



Inoceramus simpsonii. 

 Inoceramus pennatus. 

 Inoceramus subtriangulatus. 

 Inoceramus brownii. 

 Inoceramus concentricus. 

 Inoceramus platinus. 

 Inoceramus fragilis. 

 Haploscapha. 



Haploscapha grandis. 

 Haploscapha eccentrica. 

 Haploscapha niobrarensis. 

 Rudistse. 



Radiolites. 



Radiolites maximus. 

 Pholadidse. 

 Parapholas. 



Parapholas sphenoideus. 

 Cephalopoda. 

 Decapoda. 

 Teuthidae. 



Tusoteuthis. 



Tusoteuthis longus.. 



AKTHROPODA. 



Crustacea. 

 Cirripidee. 



Stramentum. 



Stramentum haworthii.. 

 Stramentum tabulatum^ 

 Squama. 



Squama spissa. 

 Squama lata. 



Description of Species in the Niobrara Formation. 



PROTOZOA. 



For descriptions and figures of the Protozoa, see Part vn. 



CCELENTERATA. 



Sponge spicules occur in the chalk of the Ornithostoma beds, 

 showing the presence of members of this class in the Niobrara 

 seas of Kansas. See Part vn. 



ECHINODERMATA. 

 Uintacrinus socialis Grinnell. Plates lxxi, cxii, cxiii. 



Uintacrinus socialis Grinnell, 1876, Am. Jour. Sci., vol. xn, p. 81; Meek, 

 1876, Bull. U. S. Geol. Surv. Terr., vol. ii, p. 375; Clark, 1893, Bull. U. S. 

 Geol. Xo. 97, p. 21, pi. i, ff. la-c, and pi. n, ff. la-e; Williston and Hill, 1894, 

 Kans. Univ. Quart., in, 19; Bather, 1895, Proc. Zool. Soc. Lond., pp. 974- 

 1004, pis. liv-lvi. 



Revised description : " Body subglobose, with ten long radi- 

 ating arms ; basal plate small pentagonal, surrounded by five 

 subradial, quadrangular plates. The six plates (one basal and 



