Length of figured specimen (PI. 2, Fig. 9b) 0.63 

 mm, height 0.41 mm, convexity 0.28 mm. 



Remarks. — The subtriangular shape together 

 with eye tubercles, overlap relationships and weak 

 surface pitting ally the present specimens with 

 those described by Alexander (1929, p. 71) from 

 the Grayson Shale (upper Albian) of northeastern 

 Texas. 



Occurrence. — Rare in the lower member of 

 Atkinson Formation, Humble Oil and Refining 

 Company's No. 1 Bennett and Langdale well, 

 Echols County, Georgia, core sample 3,700-3,710 

 feet. The species was originally described from 

 the Grayson Shale of Texas. 



Schuleridea dorsoventrus (Vanderpool) 



Plate 4, Figures 6a-c, 7a, b 



Bairdia dorsoventrus Vanderpool, 1928, Jour. 



Paleont., v. 2, p. 98, pi. 13, figs. 3, 4. 



Howe and Laurencich, 1958, Introd. Study Cre- 

 taceous Ostracoda, p. 69, text fig. 

 Bairdia glenrosensis Vanderpool, 1928, Jour. Pa- 

 leont., v. 2, p. 100, pi. 13, figs. 1, 2. 



Howe and Laurencich, 1958, Introd. Study Cre- 

 taceous Ostracoda, p. 70, text fig. 



Shell subovate to subtriangular in side view, 

 highest slightly anterior to middle ; dorsal margin 

 strongly convex, subangulated medially, truncat- 

 ed behind position of greatest height; ventral 

 margin gently convex to nearly straight ; anterior 

 margin broadly and nearly uniformly rounded, 

 slightly extended below ; posterior margin nar- 

 rowly and subacuminately curved, strongly ex- 

 tended below, truncate above ; the above features 

 of outline apply to larger left valve; outline of 

 right valve is straightened mid-dorsally, and 

 slightly sinuous ventrally. Left valve larger than 

 right, overlapping around entire periphery and 

 over-reaching right strongly along dorsum and 

 venter. Valves not strongly convex, terminal 

 areas slightly compressed, posteromedian por- 

 tion of shell somewhat swollen. 



An oblique anterodorsal swelling, presumably 

 the eye tubercle, is defined on its ventral side by 

 a shallow oblique furrow. General surface of 

 valves smooth. 



Hinge structure, as viewed by transmitted 

 light, consists of terminal, crenulate, elongate 

 sockets in left valve and intervening hinge area 

 that could not be observed clearly but dorsal to 

 which, in left valve, is a prominent accommoda- 

 tion groove. Muscle scar not seen. Radial canals 



numerous and closely spaced terminally as seen 

 in transmitted light, fewer and widely spaced dor- 

 sally and ventrally; inner lamellae fairly broad, 

 line of concrescence and inner margin nearly co- 

 incide. 



Length of holotype (PI. 4, Fig. 6a) 0.87 mm, 

 height 0.60 mm, convexity 0.37 mm. 



Remarks. — The hingement and marginal fea- 

 tures as well as the general form of the shell ally 

 this species with Schuleridea rather than with 

 Bairdia. S. hdtterasensis Swain (1952, p. 74) 

 from the subsurface Lower Cretaceous of North 

 Carolina is similar in shape to S. dorsoventrus 

 but has a densely pitted surface. 



The forms described as Bairdia glenrosensis 

 Vanderpool are apparently immature molts of 

 dorsoventrus, the latter name having page prior- 

 ity over glenrosensis. 



Occurrence. — Common in the Glen Rose and De- 

 Queen Formations at localities in northeastern 

 Texas, southern Arkansas, and northwestern 

 Louisiana according to Vanderpool (1928, p. 100). 



Genus Asciocythere Swain, 1952 

 Asciocy there rotunda (Vanderpool) 



Plate 4, Figures 3a-d, 4a-c 

 Text Figures 7a, b 



Bythocypris rotundus Vanderpool, 1928, Jour. 



Paleont., v. 2, p. 102, pi. 13, figs. 5, 6. 

 ? Cytheridea amygdaloides brevis Alexander, 



1929, (not Cornuel), Univ. Texas Bull. 2907, 



p. 70, pi. 4, fig. 13. 



Cytheridea rotundus (Vanderpool). Vanderpool, 



1933, Jour. Paleont., v. 7, p. 411. 

 ? Cytheridea amygdaloides brevis Calahan, 1939, 

 (not Cornuel), Shreveport Geol. Soc. Guide- 

 book 14th Annual Field Trip, p. 49, pi. 7, fig. 11. 

 not Haplocytheridea ? amygdaloides brevis 

 Schmidt, 1948, Jour. Paleont., v. 22, p. 426, 

 pi. 62, figs. 20-22. 

 Asciocythere rotunda (Vanderpool). Swain, 1952, 

 U. S. Geol. Survey Prof. Paper 234-B, p. 76, 

 pi. 8, figs. 22-23. 



Howe and Laurencich, 1958, Introd. Study Cre- 

 taceous Ostracoda, p. 61-62, text fig. 

 The shell of the species was described earlier 

 (Swain, 1952, p. 76). The specimens illustrated 

 here are Vanderpool's types from the Glen Rose 

 Formation about eight miles west of Weatherford, 

 Parker County, Texas, from northwestern Louisi- 



26 



