1848. | AUSTIN ON THE CYSTIDEA. 293 
Russia by Sir R. Murchison, M. E. de Verneuil and M. von Key- 
serling, it is observed, that ‘‘this family is the more interesting to the 
paleontologist, since it seems to have preceded the other Crinoidea 
in order of time, and presents, as it were, the primitive form of 
animals of this class, smce most of the genera of which it is com-— 
posed are peculiar to the Lower Silurian system, and disappear 
entirely where that terminates.” 
The opinion that this family preceded the Crinoidea is not sup- 
ported by conclusive evidence, as the remains of true Crinoids, 
furnished with rays, are found in the Lower Silurian system, and they 
were thus co-existent with the Cystidea of M. von Buch. The fact 
that several species of this family are found in the carboniferous 
limestone of Yorkshire is also opposed to M. E. de Verneuil’s asser- 
tion, that animals of this family disappear entirely where the Lower 
Silurian rocks terminate. 
In order to show that no doubt can exist as to the generic identity 
of the fossils alluded to, it may be stated that M. von Buch, in No. 5, 
page 39, of the Geol. Journal, claims two species of our proposed 
genus Sycocrinus as Cryptocrinites (Cystidea), and laments that 
the locality of these specimens was not given, or that the Crinoids 
with which they were found associated were not enumerated. This 
omission I now rectify by stating that they occur in the carboniferous 
limestone of Yorkshire, and are associated with the following species 
of Crinoidea:—Amphoracrinus Gilbertsoni (Austin), Actinocrinus 
Gilbertsoni (Miller), Platycrinus mucronatus (Austin), P. rugosus 
—with a new species of Pentremite, which M. von Buch alludes 
to at page 29, No. 5, Journal, and which in 1842 we named 
Pentremites astraformis (vide Annals of Nat. Hist. vol. x. page 111). 
The singular fossil for which we have proposed the name of Astro- 
erinus tetragonus also occurs in the same locality. Two out of our 
three species of Sycocrinus are considered by M. von Buch as 
Cryptocrinites, and therefore come within his family of Cystidea, 
while the Sycocrinus clausus he admits to belong to a new genus, but 
which must also be ranged with the same group, either as Cystidea, 
or in the family Spheeronide of Gray, in which we had previously 
placed them. 
I perfectly agree with many of the observations advanced by Dr. 
Alex. von Volborth in the introductory chapter of his Memoir on the 
Russian Spheronites, but want of space obliges me to confine my 
remarks to one or two points relating to the Cystidea. That many 
species of this group, as defined by M. von Buch, had arms, no one 
can doubt ; and although the rays in some are not similarly placed as 
in true Crinoids, yet their presence renders it necessary to separate 
the rayless species from those which are furnished with arms and 
tentacula. 
The foregoing observations are made with great deference to the 
distinguished paleeontologists from whose opinions I have ventured 
to dissent, but with perfect confidence as regards the correctness of 
the facts adduced in support of my own. 
It is worthy of observation that a large species of Echinocrinus 
VOL. IV.—PART I, Z 
