REPORT OF THE DIRECTOR I9IO 181 



McChesney, but has its beaks less elevated and is relatively longer. 

 It is very closely allied to N. tumid a, but is more pointed anter- 

 iorly. In form it resembles N. i 1 1 i n o i s e n s i s Worthen, but 

 has strong crenulated surface marks instead of being nearly glab- 

 rous. It differs from all of these in its minute size and probably in 

 its surface markings. 



Nucula sp. 



Shell of moderate size for Nucula, beaks scarcely passing above 

 the hinge. Shell inflated below the hinge, mostly broken away. The 

 surface marks consist of very fine, even, closely spaced filiform 

 striae as shown on cast. Specimen originally about lo mm long, 

 5-6 mm high and 5.5 mm thick. 



Parallelidon? sp. 



A shell apparently belonging to this genus, with long straight 

 hinge, elongate posterior border and nearly straight ventral margin 

 so far as can be told from the compressed specimen. The anterior 

 margin appears to pass obliquely forward and then downward, 

 sharply curved from the end of the hinge. Surface marked with 

 fine, regular growth lines and a few very indistinct concentric 

 undulations. 



Dimensions. Length, 21.5 mm; height, 7 mm; length of hinge, 

 about 12 mm. 



Remarks. This specimen is hardly well enough preserved to 

 identify or describe specifically in this genus where slight variations 

 of form are so vital. 



Schizodus cuneus Hall? 



Cytherodon (Schizodus) cuneus Hall. Palaeontology N. Y. 

 V. 5, pt I, Plates and Explanations, pi. 75, fig. 29, 30. 1883. 



Schizodus cuneus Hall. Idem. p. 458, pi. 75, fig. 29, 30, 1885 ; Her- 

 rick, Bull. Denison Univ., 111., p. 65, pi. 5, fig. 15, 1888; Geol. Surv. Ohio, 7, 

 pi. 21, fig. 15, 1895- 



Shell small, ovate-cuneate ; length about one-fourth greater than 

 the height; basal margin broadly curved. Post-inferior extremity 

 angular. Posterior margin very obliquely truncate. Cardinal line 

 equal to about half the length of the shell. Anterior end short, con- 

 tracted just below the beak and regularly rounded below. 



Valves gently convex below, becoming gibbous in the middle. 



Beaks at about the anterior fourth, moderately prominent. 

 Umbonal slope angular, defined, extending to the post-inferior 

 extremity. 



Surface marked by fine fasciculated striae, the remains of which 

 are still preserved in the cast. 



