HETEROCRINIDAE 
105 
CREMACRINUS Ulrich 
Plate 28 
Cremacrimis Ulrich, 14th Ann. Rep. Geol. Surv. Minnesota, 1886, p. wy.—Castocrinus Ringueberg, Ann. 
New York Acad. Sci., 4, 1889, p. 392. — Bather, Crin. Goth, 1893, pp. 56, 61 ; Treatise on Zooh, Echino- 
derma, 3, 1900, p. 148. — Zittel, Grundziige Pah, i, 1910, p. 152 . — Cremacrimis Zittel-Eastman, Textb. 
Pah, 2d ed., 1913, p. 213. — Bassler, Bibliogr. Index, Bull. 92, U. S. Nat. Mus., 1915, p. 288. 
Arm-bearing rays 4. Calyx unsymmetric. Stem not in plane of anal tribe, 
blit lying to the right of it. Median ( 1 . ant.) arm simple, or branching once; the 
inferradial of its compound radial quadrilateral, connecting with siiperradial : 
])rimibrach always short. I.ateral arms 3, two on ant. side and one on 1. post., 
each dividing into two equal and symmetrical rami, heterotomoiis, bearing alter- 
nate ramiiles at intervals of 2, 3, or sometimes 4 brachials; primibrachs 2, the 
axillary with articulating faces equal. R. post, superradial supporting anal 
tube, and r. ant. superradial the r. ant. arm, which is usually smaller than ant. ; 
the two superradials meeting above the stem-facet; r. post, and r. ant. infer- 
radials separated from one another and from anal x by their respective super- 
radials. Basals 4, all in contact with the stem; the two left BB entering into, or 
touching by their points the stem-facet; also much narrower than the others, 
and their outer sides making a reverse curve. Proximal margin of radials bor- 
dering hinge often strongly denticulate. 
Genotype. Cremacrinus punctatus Ulrich. 
Distribution. Ordovician and Silurian ; America. 
A widely distributed form of the Trenton or underlying horizons, occurring at various 
localities in Canada, New York, Minnesota and Kentucky, from which seven species have 
been described, and passing up into the Silurian in Tennessee, with four hitherto undescribed 
species herein illustrated. It is not known outside of America. The genus forms a section 
by itself, broadly differentiated from all others of the family by its 3 heterotomous lateral 
arms and asymmetric stem. 
Cremacrinus ulrichi new species 
Plate 28, figs, i, 2 
Crown relatively large for the genus, about 40 mm. high in two specimens. 
Median ( 1 . ant.) arm fairly strong at the base, about as long as the adjacent 
lateral arms, and tapering to a narrow point; consisting of about 7 brachials, 
long and slender beyond the short IBr ; inferradial elongate rectangular, broadly 
connecting with superradial. Main rami of ant. and 1 . post, arms giving off 
from successive series of 2 or 3 brachials — Alphabrachs, Betabrachs, etc. — 
alternately at each side a large ramule the full length of the arm, composed of 
one short and several long ossicles, ending with an equal bifurcation, to a total 
of 6 or 7 ramules to each ramus. R. ant. arm much smaller than the others, and 
