On Certain CrinoUi Genera. — Spri)iger. 93 
this group a series of generic forms, based on the migration 
and disappearance of the radianal, parallel to that occurring 
in the Inadunata. For we have Sagenocrinns, like Thenar- 
ocrinus, with the radianal located between two basals, and 
resting under the left half of the right posterior radial ; the 
present form, T. tuberculafiis, like Dendrocrinus, with the 
radianal lifted out of the ring of basals, and resting upon 
them directly underneath the right posterior ray; Gnoriino- 
cri lilts, like Bofryoerinus, with radianal resting on basals, 
but reduced in size and shifted to a position under the left 
corner of the right posterior radial; and Ta.vocrinns, like 
CyatJioci inns, with the radianal entirely eliminated. 
Phillips' definition of Ta.vocrinns was in very general 
terms. The truth is that what he recognized under this 
name was the type which belongs to the Flexibilia Impin- 
nata, as distinguished from the Inadunata, and he did not 
really define any generic type limited as we now under- 
stand it. It was a parental form, just as Poteriocrinus and 
ActinocrJnns were in their respective groups. His figures 
and descriptions of the species referred by him to the genus 
show plainly enough the general type which he recognized, 
but it is not so easy to determine what precise form of it 
should remain under his genus. If De Koninck and Le 
Hon's proposal for restricting the genus to species without 
interradials were accepted, and it would exclude nearly all of 
the species referred to it by Phillips, and the result would 
be simply to substitute their genus for his. Phillips did not 
designate any species as the type of the genus, but named 
four as belonging to it, — three of them described by him- 
self. His first named species, T. cgertoni, so far as can be 
judged from the figure and description, is doubtful, and 
may belong to Onychocrinns, which, however, has the same 
anal structure. But his other two species, T. nobilis and T. 
macrodactylns, seem beyond question to be of the type which 
has been taken by the later authors generally to be that of 
Taxocrinus, viz: with few or no interbrachials, and anal 
plates in a vertical series supported on a truncate or exca- 
vate posterior basal, probably forming a small tube. This 
is substantially the definition adopted by Mr. Bather in 
Lancaster's Treatise on Zoology, Part III. p. 189. 
