Cincinnatian and Lexington Fossils 37 



low, as in ordinary specimens of that species. Since the contrast 

 between the two species consists chiefly in the much greater promi- 

 nence of the plications in Cydocoelia crassiplicata, the difference is 

 much greater to the eye than indicated by the accompanying 

 ilhistrations. 



Cyclocoelia sectostriata, Ulrich. 



(Plate III, figs. 15 A, B.) 



Cyclocoelia sectostriata, Ulrich is something more than a 

 multiplicate form of Cyclocoelia clla. About 21 plications origi- 

 nate sufficiently near the beak to be called ]:)rimary. An approxi- 

 mately equal number is intercalated within 3 mm. of the beak, so 

 as usually to alternate with the latter, and additional plications are 

 intercalated anteriorly, bringing the total number up to about 50 in 

 a specimen 8 mm. in length. The type, 10 mm. in length, w^as 

 described as possessing 30 to 35 primary plications increasing to 

 about 70 at the margin. Specimens of this type occur in the 

 upper Fairmount. The specimen represented by figure 21, on 

 plate 7, of the Tzventyfourth Report on the New' York State 

 Cabinet of Natural History may belong here. The original 

 specimen is preserved in the Dyer collection in the Museum of 

 Comparative Zoology, at Harvard University, and is well repre- 

 sented by the published figure. The prominence of several of the 

 median plications of the brachial valve may be an individual char- 

 acteristic. The chief difference consists in the absence of additional 

 intercalated plications toward the margin of the shell. 



Trematis punctostriata, Hall. 



(Plate V, fig. i.) 



Shell large, attaining a width of 30 mm. ; nearly circular, 

 width a little greater than the length. Brachial valve moderately 

 convex, the convexity increasing toward the beak. Shell pitted, 

 the pits arranged in radiating rows. Along the anterior half of 

 the shell, and laterally, the pits are larger, and the rows are closer 

 together. Eight to eleven rows occupy a width of two milli- 

 meters. The rows evidently increase by intercalation. Posteriorly, 

 especially along the umbonal part of the shell, the radiating rows 

 are more distant, and appear like narrow grooves crossing an other- 



