BATOCRINID.2. 449 
Horizon and Locality. — Upper Burlington limestone, Burlington, Iowa. 
Types in the Museum of Comparative Zodlogy. 
Liemarks.— This rare and beautiful species is readily recognized by the 
peculiar form of its base, the large nodes upon the radials and interbrachials, 
and the flat plates in the upper part of the dorsal cup. The nodes upon the 
radials hang downward, and their extremities reach almost to a line with the 
lower end of the basals. 
Macrocrinus gemmiformis (Harz). 
Plate XXXVI. Fig. 8. 
1860. Actinocrinus gemmiformis — Haut; Suppl. Geol. Rep. Iowa, p. 28 (Photogr., Plate 3.4, Fig. 6, 1872, 
N. Y. State Museum, Bull. I.). E 
18783. Batocrinus (Hretmocrinus?) gemmiformis —Muzx and Worturn; Geol. Rep. Illinois, Vol. V., 
p- 368. 
1877. Batocrinus gemmiformis— 8. A. Minter; Catal. Paleoz. Foss., p. 72. 
1881. Hretmocrinus gemmiformis — W. and Sp. ; Revision Paleocr., Part IL., p. 173. 
1890. Eretmocrinus gemmiformis —S. A. Mruunr; North Amer. Geol. and Paleont., p. 243. 
A small and delicate species. Calyx a little higher than wide. Dorsal 
cup truncate at the bottom; the sides moderately and uniformly rising to 
the arm bases; higher than the ventral disk. Plates elevated; the radials 
covered with long transverse nodes or obtuse spines, and similar elongate 
nodes, but circular in outline, are formed on the second costals, the first 
interbrachials, and the anal plate; the distichals and palmars angular on the 
back, forming distinct ridges. 
Basals produced into long spreading extensions, which overhang the 
upper part of the column, giving to the base a decidedly trilobate outline. 
Radials large, a little wider than long. Costals less than half the size of the 
radials, almost as long as wide; the first quadrangular; the second pent- 
angular. The anterior ray has 3 X 2 distichals; the four other rays have in. 
one division two small distichals, followed by two palmars, in the other three 
distichals. There are fourteen arms to the species, exceptionally fifteen or 
sixteen, the odd number occurring in the antero-lateral rays. The upper 
brachials are in contact laterally except on the anal side, where they are 
separated by an elongate piece, which connects with the plates of the disk. 
Structure of arms unknown. Anal plate higher than the radials, supporting 
three large plates, and these from two to three small ones ; the interbrachials 
at the four regular sides consist of two to three plates. Ventral disk hemi- 
spherical; the plates large and sharply nodose. The posterior oral forms at 
B7 
