190 C. Wachsmuth—Structure of Paleozoic Crinoids. 
their summit structure from the general plan; but I have yet to 
discover a single Paleozoic genus in which a special oral aper- 
ture has been identified, or in which the existence of a solid 
furrow, recedes in Paleozoic Crinoids one step further and dis- 
appears within the solid walls of the body. The actinal sys- 
tem here consists externally only of the arm furrows, whence it 
continues underneath the vault. These Crinoids therefore are 
evidently of lower development and belong to an inferior type. 
The ventral peristome of the recent Crinoids serves as a mad- 
reporic apparatus, introducing the necessary water for respira- 
in which the actinal side is closed, represent the young stage 0 
growth of the living types. They ee evidently the same re- 
lation to the Pentacrinide and Comatulide as the Perischoechinide 
bear to the Echini, as the Cystidee and Blastoidece bear to the Pa- 
leozoie Crinoids. They unquestionably form a distinct group ot 
Crinoids, and I therefore propose for it, from the fact that 1ts 
representatives lived almost exclusively in Paleozoic times, the 
name: “ Paleocrinoidea” as a suborder of the Crinoids. 
Whether Encrinus, Apiocrinus and allied genera of the Juras- 
sic time are to be brought within this suborder, depends upot 
the construction of their vault, which cannot at present be de- 
