PELEGYPODA. Ill 



MOLLUSCA 



Class PELECYPODA 

 Order Prionodesmacea 



Family Solemyacidae 



Genus Clinopistha Meek and Worthen 



Clinopistha? rowleyi n. sp. 



Plate 25, figures 7 and 8 



Description — Shell of medium size, suboval; height about two-thirds the length; 



basal margin gently and almost uniformly curving; posterior end rounded to truncate; 



anterior end rounded to pointed; part in front of the beaks about half as long as the 



part behind the beaks. Valves moderately to strongly convex. Surface marked with 



moderately coarse concentric lines of growth. 



No specimen has the hinge well preserved and the generic reference is, of course, 

 uncertain. The species differs from Clinopistha antiqua Meek, in the greater length 

 anterior to the beaks and shorter length posterior: 



Occurrence — Near the top of the Snyder Creek shale of Callaway County. 



Family Grammysiidae 

 Genus Grammysia Verneuil 



Grammysia elliptica Hall 



Plate 25, figures 15 and 16 



1870. Grammysia elliptica Hall, Notice Lamellibranchiata, II, p. 53. 



1885. Grammysia elliptica Hall, Pal. of N. Y., V, pt. 1, pp. 365-366, pi. 58, figs. 1-12. 



1913. Grammysia elliptica Clarke and Swartz, Maryland Geol. Survey, Middle and 



Upper Devonian, p. 606, pi. 59, figs. 11-12. 



Hall's description — "Shell of medium or large size, transversely elliptical; length 

 varying from one-sixth to one-third greater than the height; basal margin broadly 

 curving, slightly sinuate about the middle; posterior margin abruptly rounded below 

 and curving into the cardinal line 'above, sometimes more or less truncate. Cardinal 

 line arcuate. Anterior end narrow and abruptly rounded below the lunule. 



Valves regularly convex below, becoming more or less gibbous above the middle 

 and in the umbonal region. 



Beaks sub-anterior, very prominent, strongly incurved, rising considerably above 

 the hinge line. Umbonal slope rounded, arcuate. Cincture consisting of a fold and 

 furrow, extending downward in a curving direction to the base of the shell, producing a 

 gentle sinuosity in the basal margin. The fold is more strongly developed in the left 

 valve and the furrow in the right one. 



Test thick, marked on the posterior and middle portions of the shell by fine, irregular, 

 concentric striae, which become aggregated into fascicles on the middle of the shell; 

 and on the anterior part marked by strong concentric undulations. No radiating striae 

 have been observed. 



The hinge of the right valve shows a thickened plate bearing a single angular fold 

 just beneath the beak. Nothing is satisfactorily known about the muscular impressions. 



Four specimens measure respectively 31, 57, 65 and 93 mm. in length, and 23, 36, 

 46 and 63 mm. in height." 



Remarks — This form is rare and all specimens in the collections are imperfect. 

 The identification, however, is fairly certain. 



Occurrence — Snyder Creek shales of Callaway County, location 2. 



