490 SYSTEMATIC PALEONTOLOGY 



south of Chesapeake R. E, Bridge, 1 mile northwest of West River, 

 1 mile east of Marriott Hill. 

 Collection. — Maryland Geological Survey. 



SCEPTRONEIS GEMMATA GrunOW. 

 Genus SYNEDRA Ehrenberg. 



Synedra linea Ehrenberg. 

 Family TABELLARIE/E. 



Genus GRAMMATOPHORA Ehrenberg. 



Grammatophora striata var. rossiLis Grunow. 



Tribe CRYPTO-RAPHIDIE/E. 



Family CH/ETOCEROS. 



Genus DICLADIA Ehrenberg. 



DiCLADiA capreolus Ehrenberg. 



Genus HERCOTHECA Ehrenberg. 



Hercotheca neammilaris Ehrenberg. 



Genus PERIPTERA Ehrenberg. 



Periptera tetraoladia Ehrenberg. 



Genus CH/€TOCEROS Ehrenberg. 



CH.a;TOCEROs diploneis Ehrenberg, 



Genus DITYLIUM Bailey. 



DiTYLiuM undulatum Ehrenberg. 



Genus STEPHANOPYXIS Ehrenberg. 



Stephanopyxis apiculata Ehrenberg. 



Stephanopyxis corona (Ehrenberg). 



Plate CXXXV, Fig. 13. 



Systephania corona Ehrenberg, 1844, Monatsb. d. k. Akad. d. Wiss., Berlin, p. 373. 

 Systephania corona Ehrenberg, 1856, Mikrogeologie, pi. 33, xv, fig. 33, etc. 

 Stephanopyxis corona Van Heurck, 1881, Syn. Diat. Belg. pi. Ixxxiii, ter. figs. 10, 11. 



Description. — Valves circular, dissimilar. Surface flat or convex, 

 closely reticulate, the cells equal. A dense row of spines is placed near 



