ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK I25 



HERCOCRiNus gen. nov. 



spKoi, a snare; Kpivov, a lily 



Genotype Hercocrinus elegans 



■ Calyx more or less flattened at the base with a basal narrow con- 

 cavity involving less than half of each basal; infrabasals very 

 small and completely covered by the column. Radials nearly equal 

 in size to exposed portion of basals. Primibrachs two, first se- 

 cundibrachs are unsymmetrical secundaxils each giving off a large 

 pinnule which is incorporated with the cup and the first joint of 

 which meets its neighbor over the topmost interbrachial ; all sub- 

 sequent brachials also bear pinnules and the first two of these are 

 also incorporated with the cup or meet to form a weblike extension 

 of the bases of the arms. Arms two to each ray, the brachials of 

 each zigzag up to at least the tenth, beyond that unknown ; inter- 

 secundibrachs absent. Tegmen of very numerous small plates 

 forming a basin whose margins extend upward on the arm bases 

 and whose -center is more or less elevated in a nearly central mound 

 containing the anus. Interradii often differing from each other 

 in the arrangement of their plates, the radials usually separated from 

 each other by two interradials. One or more larger central or 

 eccentric plates more or less surrounded by other interbrachials. 

 Supplementary plates present but not so numerous or so regularly 

 arranged as in Deocrinus. Anal interradius not to be clearly dis- 

 tinguished from the others. Stem circular, lumen about one sixth 

 the stem diameter, pentagonal, the angles at the stem joints and 

 therefore radial in position. 



Remarks. Hercocrinus may be distinguished from Diabolo- 

 crinus by its narrow basal concavity ; its completely covered in- 

 frabasals ; its interradial spaces do not " connect with the disc 

 plates, or, properly speaking, pass into the disc" [W & S] ; the 

 anal interradius is not wider than the others, the ventral disc is 

 composed of very small, not " rather large plates " and the column 

 does not possess a pentalobate canal. The tegmen is more like 

 that of Archaeocrinus but the calyx is not elongate, the arms do 

 not branch and supplementary plates are numerous. 



Hercocrinus elegans sp. nov. 



Plate q; cup analysis figure 6 of text 



Description of type. Cup 12 mm wide, 7 mm high, base flat- 

 tened, rather pentangular. 



