North Carolina Stale Library 

 Rafei^fo 



rounded, that of right valve strongly rounded and 

 drawn out into median bulbous extension, trun- 

 cated. Right valve larger and overlapping left 

 valve, greatest anteriorly and dorsally. Surface 

 smooth. Internal features not observed. 



Dimensions : Fig. 3 : length 0.87 mm ; height 

 0.44 mm; biconvexity 0.33 mm. 



Occurrence: Peedee only, localities A and E. 

 U.S.N.M. 128890, 128891, 128892. 



Remarks : The bulbous posterior extension of 

 the right valve serves to readily distinguish this 

 species. 



Cytherella herricki Brown, n. sp. 

 Plate 1, Figures 8-11 



Shell subovate-elongate in lateral view; great- 

 est height slightly anterad of median ; dorsal mar- 

 gin moderately convex; ventral margin straight; 

 anterior margin broadly and evenly rounded ; pos- 

 terior margin rounded. Right valve larger than 

 left, overlapping around entire periphery, great- 

 est anterad dorsally. 



Surface finely punctate, coarser medially, with 

 a faint "crescent-shaped" median sulcus extend- 

 ing from just inside dorsal margin to center of 

 valve; anterior margin of left valve bears a fine 

 sharp rim below, more pronounced medially.- In- 

 terior of valves deep posteriorly and showing a 

 smooth ridge marking position of median sulcus, 

 otherwise smooth. 



Dimensions : Holotype : length 0.74 mm ; height 

 0.42 mm; biconvexity 0.25 mm. 



Occurrence : Peedee only, localities A, C, and F. 

 U.S.N.M. 128893, 128894, 128895, 128896. 



Remarks: The punctate surface and median 

 sulcus serves to readily distinguish this species. 

 Specimens which bear a slightly extended and 

 inflated posterior area in the right valve and a 

 very faint anterior swelling ventrally in the left 

 valve probably represent female dimorphs. Named 

 for Dr. Stephen Herrick, U. S. Geological Survey. 



Cytherella sp. 

 Plate 1, Figures 1, 2 



Ovate valves of Cytherella occur frequently in 

 many of the Peedee outcrops. They are generally 

 short in relation to width and contain a faint ill- 

 defined depression dorso-medially. No attempt 

 was made to further identify these specimens as 

 no complete carapaces showing overlap relation- 

 ships were present in the material examined. 



Dimensions : Fig. 1 : length 0.85 mm ; height 

 0.53 mm; convexity 0.13 mm. 



Occurrence: Peedee only, localities A, B, C, D, 

 and E. U.S.N.M. 128897, 128898. 



Remarks : Common in subsurface Peedee 

 (upper part). 



Genus Cytherelloidea Alexander, 1929 



Cytherelloidea swaini Brown, n. sp. 



Plate 1, Figures 16-19 



Shell short, quadrate in side view ; dorsal mar- 

 gin slightly convex, sinuous ; ventral margin 

 straight ; anterior margin broadly rounded ; pos- 

 terior margin more narrowly rounded. Right 

 valve larger and overlapping left, greatest at an- 

 terior dorsal angle. 



Anterior margin with broad sloping rim and 

 subjacent depression posterad; sharp ventral rim, 

 connected with anterior rim at anterior ventral 

 angle, forms ventral margin passing posterad into 

 large high tubercle located at posterior ventral 

 angle; a second large high tubercle lies at pos- 

 terior dorsal angle ; a bulbous dorsal ridge rises 

 postjacent to and slightly forward of the an- 

 terior dorsal angle, curves gently towards the an- 

 terior dorsal angle, and forms the dorsal margin 

 passing posterad into the dorsal tubercle. There 

 is a deep subcentral depression. Touching the 

 ventral margin, medially, is a thick bulbous ridge, 

 anterad rising upward and passing into the ante- 

 rior third of the valve, posterad rising upward 

 and passing into posterior third of valve just 

 short of the ventral tubercle. A short rim along 

 the posterior margin connects dorsal and ventral 

 tubercles. Interior of valves, rugose, deep pos- 

 teriorly. 



Dimensions : Holotype : length 0.58 mm ; height 

 0.36 mm; biconvexity 0.22 mm. 



Occurrence: Peedee only, localities A, B, C, D, 

 E, and F. U.S.N.M. 128899, 128900, 128901. 



Remarks : This species which can be distin- 

 guished by the large posterior tubercles and slop- 

 ing anterior rim is an excellent guide fossil for 

 the Peedee formation. Named for Professor Fred- 

 erick M. Swain, University of Minnesota. 



Cytherelloidea (?) cuneiforma Brown, n. sp. 

 Plate 1, Figures 13-15 



Carapace in lateral view, oblong-subovate ; dor- 

 sal margin straight, slightly arched in posterior 

 third ; ventral margin straight to weakly concave 



