- — al ie =e a a . : _ 
SS NSS Se ee 
BATOCRINID &. ; 48] 
Horvzon and Locality. — Upper Burlington limestone, near Sedalia, Mo. 
Type in the collection of Mr. F. A. Sampson, Sedalia. 
Remarks. —'The obconical form of the cup, and the almost flat disk, are 
the leading characters of this species, in which it approaches A. spinosulus 
Hall. However, the calyx of that species is deeply grooved at all sides, and 
the rays are separated by numerous interbrachial plates which pass up to 
the plates of the disk. 
Aorocrinus helice (Hatt). 
Plate XLV. Figs. 2 and &. 
1864. <Actinocrinus helice — atu; 17th Rep. N. Y. State Cab. Nat. Hist., p. 53. 
1878. <Actinocrinus helice— Wau; Geol. Surv. Ohio, Palzont., Vol. II., p. 163, Plate 11, Figs. 5 to 8. 
1881. <Agaricocrinus helice—W. and Sp.; Revision Paleocr., Part IT., p. 112 (Proceed. Acad. Nat. Sci. 
Phila. p. 286). 
Syn. Actinocrinus helice, var. eris Haun; Geol. Surv. Ohio, Paleont., Vol. II., p. 164, Plate 11, . 
Figs. 9 to 10. 
Syn. Agaricocrinus eris — W. and Sp.; 1881, Revision Paleoer., Part II., p. 112. 
Approaching in the form of the calyx, and the stoutness of its arms, 
some of the aberrant smaller forms of Agaricocrinus. Calyx wider than 
high, the summit crowned with an elongate node or short spine. Dorsal cup 
short, rapidly spreading to the arm bases, rounded at the bottom, the lower 
margins of the radials bending inward and taking part in the truncation at 
the bottom. Surface of plates nodose, the radial ones transversely angular, 
the interradial ones with obscure radiating ridges along the margins, 
Basals small, arranged almost horizontally ; only small portions of them 
being exposed in a side view; the interbasal sutures deeply channeled at 
the lower end. Radials large, rapidly spreading upwards; the upper face 
slightly notched at the sides. First and second costals together smaller 
than the radials; the first quadrangular, the second pentangular. Distichals 
short, consisting in the anterior ray of three rows of plates in the calyx, of 
which those of the first row are somewhat larger than the two of the suc- 
ceeding ones, the latter being as short as the free brachials above, and like 
them rounded on the back. In the posterior rays both first distichals are 
axillary, and support from each side two short fixed palmars. In the two 
antero-lateral rays normally the distichals next to the posterior rays are 
axillary and support palmars, the others are followed by other distichals; 
it occurs, however, also that none of them are axillary or both of them; the 
number of arms thus varying from twelve to sixteen. Arms rounded on 
61 
SS rea pe ar a 
