36 Aug. F. Focrste 



Cyclocoelia sordida, Hall. 



(Plate II, fig. 10; Plate VI, fig. 8 A, B.) 



The type of Cyclocoelia sordida, Hall, (plate H, fig. lo,) pre- 

 served in the American Museum of Natural History, in New York 

 City, possesses 21 primary plications and one secondary plication. 

 The length of the specimen is 8.2 mm. and the thickness through 

 the valves is about 4 mm. 



The original description of Cyclocoelia ella, Hall, (plate II, fig. 

 II,) mentions 15 to 20 simple plications, but the first published 

 illustrations of this species, in the Fifteenth Report of the New 

 York State Cabinet of Natural History, plate 2, fig. 6, represents 

 a specimen with at least 27 or 28 plications, and figure 7 repre- 

 sents a specimen with about 22 plications. Among the specimens 

 preserved in the American Museum of Natural History in New 

 York City, and numbered 1056-3. one specimen has 27 plications of 

 which between 5 and 7 are intercalated within one millimeter of the 

 beak; a second specimen has 21 plications; and three other speci- 

 mens have 18 and 19 plications. Cyclocoelia ella is identical with 

 Cyclocoelia sordida. 



The specimens with 29 to 34 plications (plate VI, figs. 6 A, B, 

 C, D, and 7 A, B, C, D) usually begin wich about 21 primary pli- 

 cations, as in typical Cyclocoelia sordida, but the number of plica- 

 tions is increased by intercalation. These forms, here called Cyclo- 

 coelia sordida-inultiplicata, appear intermediate between Cyclocoelia 

 sordida and Cyclocoelia sectostriata, but the plications of the latter 

 species appear more angular. 



Cyclocoelia crassiplicata, sp. nov. 



(Plate III, j6 A.B,C; Plate VI, figs. 9 A-C and 10 AC) 



Among the specimens of Cyclocoelia found in the Fairmount 

 bed at Cincinnati, Ohio, occurs a species, which is usually identified 

 as Cyclocoelia ella. It possesses usually between ii and 15 pri- 

 mary plications with occasionally several additional secondary 

 plications, but the chief characteristic of this species consists not 

 so much in the smaller number of plications as in their much greater 

 prominence and angularity. This is especially noticeable in speci- 

 men possessing 18 plications, prominent and angular, while in a 

 specimen of Cyclocoelia ella with only 18 plications, the latter are 



