120 SYSTEMATIC PALEONTOLOGY 



tiary of Maryland, may be compared Avith C. marylandica. This is 

 Cy there punctata (Mlinster). Judging from illustrations alone the pres- 

 ent species must he quite distinct and so obviously that it seems highly 

 improbable that the American variety of Mlinster's species mentioned by 

 Jones, is the same as the one above described. 



Occwrence. — Aquia Fokmation. Upper Marlboro, Brooks Estate 

 near Seat Pleasant. 



Collection. — Maryland Geological Survey. 



Genus CYTHEREIS Jones. 



Cytheeeis bassleri n. sp. 

 Plate XVI, Figs. 19-21. 



Description. — Carapace oblong, length 0.80 to 0.85 mm., widest and 

 rounded anteriorly; the posterior edge more or less angular in the mid- 

 dle, straight or slightly sinuate above to the angular extremity of the 

 hinge, and with two or three spines projecting from the slightly convex, 

 lower half; edges with a thickened rounded rim, becoming obsolete near 

 the center of the flattened ventral region; hinge line straight except at 

 the antero-cardinal angle which is thickened and prominent; ventral 

 outline slightly sinuate. Valves equal, with a rounded sub-central node, 

 sometimes obscured by a network of small ridges, and a sharp ventral 

 ridge rising gradually from its inception at the antero-ventral angle and 

 ceasing abruptly at a point about one-fourth of the length of the valve 

 from its posterior extremity. A less prominent ridge runs from the 

 high end of the ventral ridge in a slightly oblique direction to the post- 

 cardinal angle and then turns forward. The whole surface is covered 

 with rather large pits arranged in more or less irregular curved series, 

 the space between the rows, especially over the central portion of the 

 valves being raised into thin and sometimes coalescing ridges. 



This species j^resents more or less close affinities with no less than 

 six of the species of Cytliere figured by Bosquet in his excellent Mono- 

 graph of the Ostracoda of the Tertiary deposits of France.' These are 

 C. hebertiana Bosq., C. ihierensiana Bosq., C. deshayeslana Bosq., C. 



' Desc. des Entomostrace's Fossiles des Terrains Tertiaires de la France et de la 

 Belgique. Mem. Couron. Acad. Beljj., Tome xxiv, 1851. 



