904 



BR. F. A. BATHER ON 



ill his classical memoir (1866, Phil. Trans. B, vol. 156, pi. 41), 

 have, in the "' ciibriform tilms" oi Antedon, a maximum diameter 

 of '02 mm., as contrasted with "3 mm. in Hypocrinus ; partly in 

 the greater relative thickness of the plates. But, so far as I 

 can make out. in a place where the stereom was already worn, 

 the inner layer, or hypostereom, was much denser, so that the 

 pores nowhere pass right through the test. 



Description of the Specimen figured by Rothpletz. (PL XC. 

 fig. 5 ife text-fig. 159.) — In its main features this agrees with the 

 holotype, and only the points of diflference need here be 

 mentioned. 



Text-fiii. 159. 



RR 



BB 



IBB 



0,00 o 



o o o 



Hypocrinus schneideri. 



Analysis of tlie cup in the specimen figured by Rothpletz. 

 The periproctal outline is dotted in. Nat. size. 



Height 13-5 mm. Posterior basal not so prominent, partly, 

 perhaps, because worn down. Greatest sagittal diameter 

 13'2 mm. Greatest transverse diameter 13"3 mm. These both 

 at about 8 mm. from basal plane. 



Stem-facet obscure, but appears iri-egularly triangular, the 

 angles directed towards the sutures between the infrabasals. 

 Greatest external diameter (in direction of 1. ant. suture) circa 

 2' 7 mm. ISTo trace of radiating grooves. 



Infrabasals. The left larger one is considerably cracked, and 

 some of the cracks in part coincide with the sutures ; otherwise 

 all the sutures are very hard to trace. Heights of IBB : 

 anterior 6-6 mm. ; right large IB 5'1 mm. along median line, 

 5"8 mm. to posterior angle ; length of posterior suture 4"7 mm. 



Measurements of Basals in millimetres: — 



