JUNE, 1906. HypsocrINUS—-SPRINGER AND SLOCOM. 271 
pound radials in Prsocrinus 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. 
