186 CRINOIDS. 



joints; central canal circular. Basals three in number, rather 

 large, of equal size, somewhat excavated for the reception of 

 the stem. Eadials large, slightly wider than high; costals 

 smaller than the radial plates. Arms long, stout, with the ex- 

 tremities turned inward ; twenty in number, equidistantly 

 placed around the periphery of the calyx ; pinnules long, com- 

 pressed, with lengthened segments ; the latter provided with 

 hooked spines. Dorsal interradials subequal in size. Primary 

 anal plate like the radials, and in the same circlet; succeeded 

 by two ossicles in the next row. Ventral parts arched, made 

 up of large tuberculose or subspinous pieces, with often smaller 

 pieces intercalated. Anal tube large,' extending beyond the 

 ends of the arms. Surface ornamented by well-defined ridges 

 radiating from the rather prominent central node on each prin- 

 cipal dorsal plate — the radial elevations becoming more and 

 more prominent toward the bases of the free arms. Ventral 

 and tubal ossicles spinous. 



Sorizon and localities. — Lower Carboniferous, Lower Bur- 

 lington limestone: Sedalia, Hannibal, Louisiana. 



Actinocrinus arrosus (Miller). 



Blairocrinus arrosus Miller, 1892 ; Geol. Sur. Indiana, 18th Ann. Rep., adv. 



sheets, p. 41, pi. vii, figs. 1-5. 

 Blairocrinus bullaius Miller, 1892 : Geol. Sur. Indiana, 18th Ann. Kep., adv. 

 sheets, p. 41, pi. vii, figs. 6-7. 



Horizon and localities — Lower Carboniferous, Kinder- 

 hook beds : Sedalia. 



Actinocrinus reticulatus Hall. 



Actinocrinus reticulatus Hall, 1861 : Desc. New Species False. Crinoids, p 2. 

 Actinocrinus reticulatus Hall, 1861: Boston Jour. Nat. Hist., vol. VII, p. 



269. 



Calyx similar to that of A. proboscidialis., but with the dor- 

 sal cup much lower and more rounded. Ornamentation con- 

 sisting of short nodes, which seldom show any indications of 

 ridges. 



Sorizon and localities Lower Carboniferous, Lower Bur- 

 lington limestone : Hannibal, Sedalia. 



