C. Wachsmuth—sStructure of Paleozote Crinoids. 181 
per cent. 
Matte No. 1 gave (phosphate method) 6°77 Cheney. 
“ 6c . 
e t Richards. 
“ j i 
Matte No. 2 (neutralized ie eda 08 Pt Richie. 
a eney 
Matte No.3 “ (phosphate method) fi ae Richards. 
41+ Hardman. 
basic acetate) 7 79 Hardman, 
Pyrrhotite No. 1 (basi acetate) *32 9 { Hardman, 
So 
“ * (phosphate method) oe Cheney 
Pyrrhotite No. 2 (phosphate method) 0 so , Richards. 
Massachusetts Institute Technology, Woman’s hee June, 1877. 
Art. XXIV.—WNotes on the internal and yeti slg of 
Paleozoic Orinoids ; by CHARLES W ACHS 
(Continued from page 127.) 
5. The construction of the summit and its value in classification. 
THE construction of the ventral disc or actinal side of the 
calyx has heretofore received less attention than almost any 
other part of the Crinoids, and thereby an important aid to 
classification has been overlooked. I think it affords a clear 
and most important distinction between recent and ancient Cri- 
placed a number of Paleozoic genera in the same — with 
5, Pp 227, 
divides “the true Cri a which are omar by an articulated 
or jointed column” into two divisions : 
a, Crinoids in which the ventral side consists of a soft ski 
om hose in which the ventral side is covered by solid ae 
oni includes with the former group, Pentacrinide, Apio- 
crinide, Eugeniacrinide, Encrinide, Cupressocrinide and Oy- 
athocrinidee This division seems to have been based on mere con- 
jecture, since a membranous ventral surface has been observed 
only in the Pentacrinide and the recent Crinoids generally, 
Richards i washings by the of a beaker. 
was Mr. Harn’ rt ta of the spuowphat and not enough 
Phosphate of soda was added to produce a white precipitate. 
