632 THE CEINOIDEA CAMERATA OF NORTH AMERICA. 



Teleiocrinus althea Hall. 

 Plate LX. Fig. 4, and Plate LXIII. Ficj. 9. 



1S61. Actinocrbms [Cttlatlocrinus) althea — Hall; Prelim. Descr. New Palseoz. Ciin., p. 13 (figured Bull. 



I. N. y. State Mus. Nat. Hist., Plate 4, Pig. 13). 

 1881. Tehiocrinus althea — W. aud Sp. ; Revision Palaeocr., Part II., p. 148. 



A large species, remarkable for the great length of the dorsal cup, and 

 the relative shortness of the tegmen ; the former being five times the long- 

 est. Width of the rim, as compared with the length of the calyx, as seven 

 to eight. Sides of the dorsal cup slightly' convex to the top of the dis- 

 tichals, then curving outward and forming a broad rim. Plates moderately 

 convex, covered with broad elongate nodes and interrupted ridges, alternat- 

 ing with pits and grooves. The ridges, as a rule, are directed to the middle 

 of the plates, but without meeting in the centre, which is occupied by a 

 more or less corrugated or pitted elevation. 



Basals large, forming a spreading cup, of which the lower margin pro- 

 jects but little bej'ond the sides of the column. Eadials a little longer than 

 broad, and more than twice as large as both costals together ; the latter 

 hexagonal and heptagonal, nearly of equal size. Distichals one third 

 smaller than the costals, wider than long. Palmars very much shorter than 

 the distichals, twice as wide as long. The succeeding brachials smaller in 

 proportion, all much wider than long. There are apparently eight bifur- 

 cations up to the edge of the rim, and nine arms to each division, making 

 eighteen to the ray, and ninety arms altogether. Structure of the arms un- 

 known. Interbrachials generally nine, in five rows, arched over by the post- 

 palmars. The anal side contains fourteen to fifteen plates. Ventral disk 

 almost flat, rising very slightly ; the plates without definite arrangement, 

 slightly convex. Anal tube central, very large at the base. 



Horizon and Locality. — Upper Burlington limestone ; Burlington, Iowa. 



Type in the Museum of Comparative Zoology, Cambridge. 



