52 
SMITHSONIAN INSTITUTION 
Platycrinidae iiidet., No. 3 
Plate II, figs. 26, 2j, 28, 2g 
A small species rather common in the Laurel limestone at St. Paul, Indiana. 
The three foregoing species are figured in order to preserve a record of their occurrence, 
hoping that future discoveries may throw more light upon them. 
Hapalocrinus Jaekel emend. Bather 
Plates II, 12 
Hapalocrimis Jaekel, Krin. Deutschl, 1895, p. 37. — Bather, Geol. Mag., 4, 1897, p. 342; Treatise on Zook, 
3, 1900, p. 156. 
Platycrinidae with 2 or more IBr; orals small; arms uniserial with cmieate 
brachials tending to biserial, branching once or twice; column large, bearing 
strong cirri. 
Genotype. Hapalocrimis elegans Jaekel. 
Distribution. Silurian to Lower Devonian ; England, Gotland, Germany, America. 
The specimens which I have referred to this genus are notable for their profuse develop- 
ment of arms and pinnules, and of strong cirri occurring in definite whorls, at intervals ex- 
tending apparently the full length of the column. The generic characters of these forms are 
not very certain. Some of them might perhaps better be placed under Cordylocrinus of 
Angelin, but the distinctions are hard to point out with confidence, and I have chosen the 
easier course by throwing them all under the one form, which is strongly typified by the 
“ Platycriniis ” retiarius Phillips of the English Silurian. This arrangement would seem to 
include both uniserial and biserial arms — a variation that may occur among the later Platy- 
crinidae within the same species, or even the same individual, incident to growth, as seen for 
example in P. liuntsvillae. A very strongly marked species from the Lower Devonian is 
figured for comparison. 
Hapalocrinus gracilis new species 
Plate II, figs, go, gi, g2 
With heavy cuneate arms and strong pinnules, and rather high tegnien 
plates, 
Hapalocrinus cirrifer new species 
Plate 12, figs, i, 2, g, 4 
Remarkable for the long, slender arms, in some specimens almost thread- 
like; the calyx is large, but details of its structure are obscure. 
Hapalocrinus pinnulatus new species 
Plate 12, fig. 5 
Calyx narrow and relatively smaller, but bearing much stronger arms and 
pinnules. 
