DESCRIPTION OF SPECIES CRINOIDEA 285 



a second palmer, from which the free arms are given off. The two series 

 of distichals and the four series of palmers in each ray are in contact 

 laterally. Interbrachials two or three in each inter-ray, the first being of 

 about the same size as the first costals and hexagonal or heptagonal in 

 form; above this there are one or two small plates of variable size and 

 form, over which the distichals and lateral series of palmers of the rays 

 on each side are in contact all the way to the free arms. Anal plates un- 

 known. Ventral disk hemispherical, composed of pentagonal, hexagonal, 

 and heptagonal plates of nearly uniform size, each of which is provided 

 with a central, spine-like tubercle. Anal tube central or nearly so. Arm 

 openings twenty. Surface of plates smooth or obscurely granular ; small 

 pointed tubercles are also present on the costals, distichals, and first inter- 

 brachials. 



The dimensions of the type specimen are : Diameter at arm bases, 25 

 millimeters ; height from top of radial plates to the base of the anal tube, 

 26 millimeters; probable total height of calyx, exclusive of the anal tube, 

 37 millimeters; height of ventral disk, 15 millimeters. 



Remarks. — This species was originally described by Meek and Worthen 

 from the Fern Glen beds at Salt Lick point, near Valmeyer, Madison 

 county, Illinois. It was later considered as a synonym of the Burlington 

 Lobocrinus pyriformis (Shnm.) by Wachsmuth and Springer, 5 but it 

 seems to be sufficiently distinct from that form to be considered as a dif- 

 ferent species. It is especially distinguished from L. pyriformis by reason 

 of the greater development of spine-like tubercles upon the plates of both 

 the dorsal cup and the ventral disk and in the smaller number of inter- 

 brachial plates. The species has not been detected in the recent collec- 

 tions of Fern Glen material and it is known only from the original type 

 specimen described and figured by Meek and Worthen. 



ACTINOCRINUS RUBRA n. sp. 



Plate 11, figures 4-5 



Description. — Calyx about as wide as high, the arm openings situated 

 midway between the top of the column and the base of the anal tube, the 

 profile view of the specimen being subquadrangular. Dorsal cup obcon- 

 ical, the sides straight from the basals to the tops of the axillary costals, 

 beyond which point the plates of the rays bend abruptly outward to a 

 nearly horizontal position for a short distance. Basal plates rather small ; 

 radial plates the largest in the calyx, nodose, with raised, rounded, radia- 

 ting ridges passing from the central node to each of the adjoining plates, 



5 North American Crinoidea Camerata, p. 437. 



