234 Systematic Paleontology 



Length of a full-grown theca 15 mm.; width and depth about 11 mm. 

 For general form, shape of individual plates and their ornamentation, 

 see the figures and diagram, fig. 7. 



This is a very abundant species at Keyser associated with Sphcerocystis 

 multifasciata, S. glohulans, and Pseudocrinites gordoni. 



Occurrence. — Helderberg Formation, Keyser Member. Keyser, 

 West Virginia. 



Collection. — U. S. National Museum. 



Fig. 7.- — Analysis of Jaekelocystis hartleyi Schuchert. 



Jaekelocystis papillata Schuchert 



Plate XXXIII, Figs. 1, 2 



Jaekelocystis papillatus Schuchert, 1904, Smith. Misc. Col., vol. xlvii, pt. ii. 

 No. 1482, p. 225, pi. xxxvii, figs. 9, 10. 



Description. — Anal area less prominent than in the other species of this 

 genus, and bounded by plates 7, 8, 13, and only a very small part of 14. 



This species differs from J. hartleyi, to which it is closely related, in 

 the more globular theca, fewer brachioles, absence of grooves along the 

 suture lines of the plates and the papillose sculpturing of the plates ; also 

 in the fact that the discrete halves of the pectinirhombs are alike and not 

 with one-half buried deeply in a pit with a high rim. Each ambulacrum 

 has from 11 to 12 brachioles on each side, while in J. hartleyi there are 17 

 in the same length. The pectinirhombs likewise have more dichopores, 

 there being from 12 to 15 in each, while in J. hartleyi there are only 

 about 8. 



Length of the largest theca 15 mm. ; width and depth 13 mm. For 

 general form and sculpturing, see pi. xxxiii, figs. 1, 2. 



