ACTINOCEINID^. 625 



Type in the collection of Hon. Delos Arnold, Pasadena, California ; other 

 specimens in the collection of Wachsmuth and Springer. 



Eemarhs. — This species differs from G. nodobrachicdus in the smaller 

 number, and the less spreading of the arms, as well as in the construction 

 of the ventral disk ; from 0. ornatissimus in the form and proportions of the 

 dorsal cup, and the ornamentation of the plates. 



Cactocrinus glans Hall. 

 Plate LIV. Figs. 5, 6a, h, 7. 



I860. Actinocrinus glans — Hall; Suppl. Geol. Rep. Iowa, p. 16. 

 1881. Actimcrinus glans — W. and Sp. ; Eevisiou Palaeocr., Part II., p. 143. 



1893. Aetinocrimis glans — Whitfield, Mem. Am. Mus. Nat. Hist. New York, Vol. I., p. 10, Plate I., 

 Figs. 11, 12. 

 Syn. Actinocrinus tliolus Hall; 1860, Suppl. Geol. Rep. Iowa, p. 35. 

 Syn. Actinocrinus eryx Hall; 1861, Descri]i. New Pal. Ciiii., p. 12. 



^ja.. Actinocrinus Blairi S. A. Milleb; 1892, Adv. Slieets Geol. Surv. Indiana, p, 35, Plate 5, 

 Pigs. 27 and 28. 



A rather large species. Calyx subovate, a little longer than the width 

 at the arm bases. Dorsal cup abruptly spreading above the distichals, its 

 height fully twice that of the ventral disk. Plates of the dorsal cup from 

 almost iiat to nodose ; the surface smooth, except that the radials occasion- 

 ally show faint indications of strife at their lower ends. Suture lines rather 

 distinct. 



Basals large, forming a cup, twice as wide as high, a little excavated at 

 the lower end, its sides slightly spreading or convex. Radials twice as large 

 as the costals, longer than wide, the upper sloping faces much shorter than 

 the lateral ones. Costals as wide as long, the first hexagonal, the second 

 heptagonal. Palmars in contact laterally, each one supporting an arm, 

 which is free from the second plate. Arm facets large, directed obliquely 

 upwards, and concave; the respiratory pores jjlaced very close to the ambu- 

 lacral openings, and the thin partition walls rarely intact ; ambulacral open- 

 ings nearly equidistant. Arms twenty, very long, moderately heavy, and 

 rounded on the back, the tips not incurving, and the spines of the pinnules 

 small. Regular interbrachials from eight to ten : 1, 2, 2, 2, 2, 1 ; gradually 

 decreasing in size in ascending order. The anal plate in large specimens is 

 followed by 2, 3, 4, 3 and 2 plates. Ventral disk regularly convex; com- 

 posed of but few, comparatively large, and almost flat pieces, of so irregular 

 arrangement that neither the orals nor radial dome plates can be recog- 



79 



