240 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
slightly excentric, forming a simple opening through the tegmen, and in 
most of the specimens covered by a Platyceras equilatera Hall. Column 
round and rather stout. 
Horizon and Locality. — Keokuk group; Crawfordsville, Ind.; Hardin 
Co., Ky.; and Keokuk, Iowa. 
Type in the Lyon collection. 
Remarks. — This species is Lyon and Casseday’s type of the genus Gon- 
asteroidocrinus. 
Gilbertsocrinus dispansus W. and Sp. (nov. sp.). 
Plate XV. Figs. 2a, 6, c, d. 
Syn. Goniasteroidocrinus lyonanus —S. A. MitteR; Geol. Surv. Illinois, Bull. 3, p. 55, Plate 4, Fig. 4. 
Of the type of Gilbertsocrinus tuberosus, but a smaller species, the arms less 
numerous, and the calycine appendages proportionally larger. Calyx some- 
what depressed, wider than high, truncated at tle bottom, the median 
portions deeply excavated. Plates convex except the radials, which are 
extended into elongate nodes or obtuse spines directed obliquely downward. 
Infrabasals small, placed at the bottom of the concavity, and almost 
covered by the column. Basals rather small for the genus; their distal ends 
curving upwards and forming together with the median portions of the 
radials a rim upon which the calyx rests, while the lower portions of those 
plates are involved in the concavity. Radials very large, more than twice 
as large as the costals. Costals and distichals of nearly the same size, 
slightly projecting over the plates of the interradial and interdistichal areas. 
Interradial areas composed of 1, 3, 3, 2, 2 plates; the middle one of the 
second and third rows a little larger, and raised somewhat above the level 
of the two outer ones; the anal side not distinct. Interdistichals three, 
longitudinally arranged. Tegmen flat, with five deep interradial depres- 
sions, of which the posterior one is twice as large as the others; all of them 
oval in outline, and surrounded by a series of nodose pieces. The anal open- 
ing occupies the inner end of the larger depression, and in perfect specimens 
appears to be closed by a pyramid of numerous very minute pieces. The 
smaller depressions are paved by four or five larger plates of irregular form. 
The appendages are given off in pairs from the calyx, being for quite 
a distance laterally connected; they are very large, slightly pendent, and 
each pair is composed of six longitudinal rows of transverse, slightly nodose 
