1881.] NATUEAL SCIENCES OF PHILADELPHIA. 321 



would warrant only a subgeneric division of the two groups, but 

 there are other characters which have induced us to separate 

 them generically. 



In our general remarks upon the family, we have shown that 

 Meek and Worthen's Strotocrinus B, for which we propose the 

 genus Teleiocrinus, in all probability, sprung off from Actino- 

 crinus, Sect. B; while Meek and Worthen's StrotocrinuH A — 

 their t^-pical form — is similarly related to Phijsetocrinus, which 

 we separate generically from Actinocrinus. The lateral rim, 

 therefore, which produces the remarkable resemblance, according 

 to our interpretation, in the form of Strotocrinus and Teleiocrinus., 

 results from modifications in the one and the same direction, but 

 which take place in different groups. We propose the following : — 

 Generic Diagnosis. — Bod}'' large ; calyx urn-shaped, subconical 

 below ; the upper part, including the higher orders of radials, 

 spread out horizontally, and formed into an extended, continuous 

 rim around the body ; vault moderately convex, with a strong 

 subcentral anal tube ; surface ornamentation similar to Actino- 

 crinus, but, as a rule, very much coai-ser, the nodes more 

 prominent than the striations, and sometimes almost entirely 

 obscuring them. 



Basals three, large, massive, projecting beyond the point of 

 attachment for the column, and frequently extended into a 

 bipartite node ; sutures deep. 



Primary radials 3X5; the first large, as high as wide ; the 

 second generally hexagonal, of the same proportions as the first 

 but smaller ; the third like the second, but angular above instead 

 of truncate. 



Secondary radials 1 X 10, axillary, supporting the two main 

 divisions of the ray. The radials of all succeeding orders are 

 composed respectivel}^ of a single series of pieces, of which only 

 one plate, of each main division, in each order, bifurcates again, 

 and this alternately on opposite sides, the other — opposite — plate 

 which is never axillary, being succeeded in a direct line by a row 

 of a variable number of fixed arm plates, which form branches 

 within the body, alternatel}^ given off from the main trunks. All 

 plates of the lateral branches and main divisions are closely 

 joined with each other, and with those of the adjoining rays, and 

 these together form the peculiar rim which surrounds the body. 

 The plates of the rim are nearly of equal size, convex, and formed 



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