190 Twenty-fourth Report on the State Museuju^ 



Formation and locality. From the crinoidal beds above the 

 "Hydraulic beds," near Louisville, Kj. Cabinet of Dr. James 

 Knapp. 



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CyPEICAEDINIA 1 CYLINDEICA n. Sp. 



Shell cylindrical, extremities rounded, height little more than'' 

 depth, and rather more than twice as long as high ; beaks nearly 

 terminal, rounded and incurved ; left valve scarcely less convex than 

 the opposite ; umbonal slope slightly angular. 



Surface marked by faint, distant, concentric, lamellose lines. 



The specimen described is essentially a cast preserving a portion 

 of the shell on one side. 



This species is more elongate and cylindrical, less arcuate, and 

 more equivalved than C. irifiata. The lamellose strise have never 

 been so strong, and are more distant. 



Formation and locality. In the " Hydraulic beds" of the age of 

 the Upper Helderberg limestone, near Louisville, Ky. From the 

 cabinet of Dr. James Knapp. 



YOLDIA? VALVULUS n. Sp. 



Shell narrow, subelliptical, more than twice as long as high ; the 

 depth a little more than half the height ; the anterior end nearly 

 one-fourth wider than the posterior. Beaks situated at three-fifths 

 the length from the anterior end ; an obsolete post-umbonal ridge 

 extending from near the beak to the post-basal margin; posterior 

 extremity not recurved. 



Surface marked by somewhat coarse, wavy, concentric lines, to 

 the post-umbonal ridge, above which they are even and much finer. 



Formation and locality. From the " Hydraulic beds," near Louis- 

 ville, Ky. Cabinet of Dr. James Knapp. 



JSTtjcula niotica n. sp. 



Shell small, obtusely cuneiform, the beaks prominent, incurved, 

 with the umbo inflated ; height from beak to base equal to three- 

 fourths the length of the shell. 



Surface marked by fine, even, concentric strige, with sometimes 

 strong varices of growth. 



The internal casts show the evidence of strong anterior and pos- 

 terior muscular impressions, and three distinct umbonal pedal mus- 

 cles, seven oj; more posterior, and five anterior teeth in a specimen 

 of medium size. The largest specimen measured is three-eighths of 

 an inch long. 



