Fig. 9) 0.73 mm, height 0.46 mm, convexity 0.26 

 mm. 



Remarks. — The small size, subquadrate outline, 

 dense pitting and small beak and notch distinguish 

 this species. 



Occurrence. — DeQueen Limestone, Gypsum 

 Bluff, near Murpheesboro, Pike County, Arkansas. 

 It has also been recorded from the Lower Cre- 

 taceous of Idaho and Wyoming. 



Superfamily Cytheracea Baird, 1850 



Family Cytherideidae Sars, 1925 



Subfamily Neocytherideinae Puri, 1957 



Genus Paracyprideis Klie, 1929 



Paracyprideis? graysonensis (Alexander) 



Plate 1, Figure 10 



Cytheridea graysonensis Alexander, 1929, Univ. 



Texas Bull. 2907, p. 72, pi. 5, figs. 3, 4. 

 Haplocytheridea? graysonensis (Alexander) 



Swain, 1952, U. S. Geol. Survey Prof. Paper 



234-B, p. 78, pi. 8, figs. 16, 17. 

 Paracyprideis graysonensis (Alexander) Howe 



and Laurencich, 1958, Introd. Study Cretace- 

 ous Ostracoda, p. 445, text fig. 



The diagnostic features of this shell are the 

 elongate pyriform shape, overlap of right valve by 

 left along all but posterodorsal edges of shell, 

 smooth surface, except for scattered pore canal 

 pits, and low relief of valves. According to Howe 

 and Laurencich the hinge of this species is: in 

 left valve, an anterior smooth socket, behind which 

 is a bar that extends back along middle of hinge 

 line, and in right valve the sharp valve edge pro- 

 jects farther at ends of hinge than in the middle. 



Length of a figured specimen (PI. 1, Fig. 10) 

 0.70 mm, height 0.40 mm, convexity 0.32 mm. 



Remarks. — The writers are not completely satis- 

 fied with the generic assignment of the specimens 

 included in this species. Until the internal struc- 

 tures are better known, particularly the hinge- 

 ment and inner lamellae of the southeastern 

 United States specimens, the assignment to 

 Paracyprideis is tentative. 



Occurrence. — Rare in lower member of Atkin- 

 son Formation, Humble Oil and Refining Com- 

 pany's No. 1 Bennett and Langdale well, core sam- 

 ple 3,690-3,700 and 3,700-3,710 feet; Sun Oil 

 Company's Tillis No. 1 well, Suwannee County, 

 Florida, core sample 3,240-3,250 feet; Sun Oil 

 Company's No. 1 Johnson well, Columbia County, 



Florida, core sample 2,955-2,965 feet; Sun Oil 

 Company's No. 1 Westbury well, Putnam County, 

 Florida, core sample 3,834-3,838 feet. The species 

 was described from the Grayson Formation of 

 northeastern Texas and has also been recorded 

 from the subsurface of North Carolina in beds of 

 Eagle Ford and older Cretaceous age. 



Subfamily Cytherideinae Sars, 1925 



Genus Fossocytheridea Swain and Brown, n. gen. 



Shell medium size, dimorphic ; females subovate 

 in side view ; males subelliptical ; dorsum moder- 

 ately to strongly convex, umbonate in females, 

 venter nearly straight in left valve. Valves moder- 

 ately convex in males, strongly convex in females. 

 Valves distinctly unequal in size, left larger, over- 

 lapping and extending beyond right around all 

 but the posterior margin. 



Hinge margin of right valve consists of an an- 

 terior elongate denticulate toothlike area, an in- 

 terterminal depressed crenulate section, and a 

 posterior denticulate tooth shorter than anterior 

 toothlike section. Muscle scar a submedian verti- 

 cal row of four spots and two additional more 

 anterior spots. Inner lamellae rather narrow, 

 broadest anteriorly ; line of concrescence and inner 

 margin nearly coincide. Radial canals fairly num- 

 erous, about 25 anteriorly, less numerous pos- 

 teriorly and sparse ventrally; anteriorly, canals 

 are expanded medially and in part occur in pairs. 

 Normal canals fairly numerous. 



Hinge of left valve comprises terminal denti- 

 culate socket-grooves and an interterminal high 

 bar, along the crest of which lies a weak crenulate 

 furrow; dorsal to bar is a distinct accommodation 

 groove. 



Free margins of left and right valves provided 

 with well developed selvage groove and flange re- 

 spectively. 



A rather narrow, shallow to deep, slightly 

 curved sulcus arises near anterior margin about 

 one-half from anterior end and extends ventrally 

 to near midheight. General surface smooth to 

 weakly pitted. 



Type species, F. lenoirensis Swain and Brown, 

 n. sp. ; geologic range, Lower Cretaceous. 



Discussion. — The new genus is similar in general 

 shape to Ovocytheridea Grekoff and Dolocytheri- 

 dea Triebel, but differs from both in having an 

 antero-median sulcus, and in details of hinge- 

 ment. It closely resembles Cyprideis Jones in 

 shape and hingement and in pronounced dimorph- 



17 



