﻿2 26 SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 47 



JAEKELOCYSTIS AVELLANA n. sp. 



(Plate XXXVII, figures ii, 12) 

 Theca shaped like a hazelnut, the resemblance suggesting the name, 

 about 10 mm. in length and breadth, in the largest of three known ex- 

 amples. Plates nearly smooth ; 

 for their individual form, see 

 the diagram (figure 28) and 

 plate xxxvii, figures 11, 12. 



Ambulacra narrow, but ap- 

 pearing wide on account of 

 their lying in rather deeply 

 <g> <^>/> (jSj ljy~y excavated thecal grooves, with 



sharply elevated margins, ex- 



Fig. 28. — Analysis of Jaekelocystis ,-. , . . , 



tending to the lower ends of 

 avellana n. sp. ° 



the second or to the top of 

 the basal circle of thecal plates. The 4 ambulacra are regularly dis- 

 posed and do not converge. Nature of brachioles unknown, about 

 26 on each ambulacrum, or 13 on each side. Ambulacrals thick, 

 causing the ambulacral furrow to be narrow ; ambulacralia not pre- 

 served. 



Hydropore conspicuous and situated as in /. hartleyi. 



Anal pyramid not preserved. Anal area less conspicuous, but 

 otherwise as in /. hartleyi. 



Pectinirhombs as in the species just cited, with 1 or 2 dichopores 

 less to each rhomb. 



Column unknown. 



Formation and locality. — Three specimens of this species are 

 known from the cystid beds of the Manlius in the quarries near 

 Kevser, West Virginia. One of these is in Mr. Hartley's collection. 



Cat. number 35,056, U. S. N. M. 



Subfamily Staurocystin^e Jaekel 



Callocystidse with the brachioles closely adjoining, and the ambu- 

 lacra highly arched and prominent. Ambulacra 2, 3, or 4 in number, 

 and never bifurcating. 



Pseudocrinites Pearce 



Pseudocrinites Pearce, Proc. Geol. Soc. London, iv, 1843, p. 160. — 

 Forbes, Mem. Geol. Surv. Great Britain, 11, pt. 11, 1848, p. 494. — 

 Jaekel, Stammesgeschichte der Pelmatozoen, Berlin, 1, 1899, p. 283, 

 fig. 60 on p. 284. 



