June, 1906. Hypsocrinus — Springer and Slocom. 271 



pound radials in Pisocrinus and Haplocrinus, and we see no reason 

 for thinking any other arrangement preferable. A peculiar fact, 

 which we have also omitted from the specific description, is that 

 the posterior basal is much larger than any of the others, and is en- 

 larged in such a way as to be actually radial in position, instead of 

 inter-radial, as basals normally are. 



We have not been able to ascertain anything of the construction 

 of the tegmen. We attempted to remove some of the overlying 

 brachial plates for that purpose, but they were found to be so firmly 

 cemented by pressure, that the only result was fracture of these 

 plates along the cleavage planes of the calcite, without revealing the 

 structures underneath. The tegmen is clearly not an elevated pyra- 

 mid like that of Haplocrinus, but beyond this, no opinion can be 

 ventured with our present knowledge. 



