212 N. Y. State Museum of Natural History. 



Genus CALCEOCKINUS, Hall. 

 Calceocrinus Barrandii, n. sp. 

 Plate 17, Jigs. 1, 2. 



Body small, somewhat flattened on the dorsal and rounded on the 

 ventral side. The swelling of the right dorso-lateral plate near its 

 basal margin gives a constricted appearance to the body about mid- 

 way of its length, when viewed from the dorsal side. 



Basal plate short, sub-triangular. First dorsal plate elongate, 

 slightly concave on the lower margin, and narrowing upward to a 

 point near the summit of, and between, the dorso-lateral plates. The 

 dorso-lateral plates are large and support the dorso-radial plates upon 

 which rest the brachial plates of the dorsal arm. 



The dorsal arm consists of a single series of subcylindrical plates. 

 The first plate above the dorso-lateral plate is broader than high, and 

 supports a pentagonal brachial plate upon which the arm bifurcates, 

 the left branch bifurcating again on the sixth plate, and the right or 

 ventral arm on the second plate, and again on the first and second 

 above : the branches again subdividing near their upper extremities. 

 Surface of body and arms granulated. Column round, composed of 

 rather thick, slightly rounded plates. 



Owing to the anchylosing of the plates of the body, it is difficult 

 to determine their outline. The description is drawn from two speci- 

 mens, each showing the dorsal and right dorso-lateral sides. 



The species resembles Calceocrinus {Heterocrinus) articulosus 

 Billings, but varies in the arrangement of the plates of the ventral 

 arms. 



The specific name is given in honor of the eminent palaeontologist 

 of Bohemia. 



Formation and location. Upper portion of the Trenton lime- 

 stone, Trenton Falls, N. Y. 



Genus METOPTQMA— Phillips. 



Metoptoma Billingsi, n. sp. 



Plate 17, Jigs. 12, 12a. 



Oval, subcorneal; apex at the most elevated point on a line with 

 the anterior margin. The outline from the posterior margin to the 

 apex is regularly convex, and from the apex to the anterior margin, 

 slightly concave. The posterior margin has a slight undulation near 

 its center. 



Surface marked by shallow undulations and lines of growth par- 

 allel to the margin. 



Length of shell, 26 mm., width, 20 mm., hight, 20 mm. 



