E. Billings on the structure of the Crinoidea, etc. 73 
Glyptocrinus nner ei esata sp.). — this extraordin- 
_ ary Crinoid is figured by McChesney in his “ New Pal. Foss.”, 
 pil.7, £6, and A is: Prof. Hall, in the 20th Reg. Rep., N. i. 
4) 10, fll. The specimens are between 2 and 3 inches in 
length. - There are ten arms, the anterior side is much inflated, 
_ the proboscis appears to be large at its base and excentric in 
_ its position, but instead of standing erect, it bends down to 
_ the surface of the vault, and lies upon it, crossing over to the 
_ posterior margin. J udging from the figures, the center of the 
base of this organ must be distant from the radial center 
at least one-fourth of the whole width of the vault. G. 
siphonatus (Hall), figured on the same plate, shows, that the 
anterior grooves curve round to the posterior side of the pro- 
boscis, as they do in B. icosadactylus above cited. 
I should also state here that two or three years ago, Mr. 
Meek, to whom I had written for information on this subject, 
wrote me that in all cases, where he had observed the grooves 
on the interior of the vault, they radiated, not from the mouth, 
but from a point “in front of it.” (This ‘would be not in front 
of, but behind the mouth, according to the terminology used in 
these notes. I think that the side in which the mouth is situ- 
ated should be called “anterior” or “ oral” even although both 
the mouth and anus should be included in it.) 
In all the species above cited, the figures (with the exception 
of C. ornatus) exhibit the relative position of the mouth and 
radial center, as it has been actually seen in casts of the inte- 
rior of the vault. But besides these, numerous examples may 
_be found in the works of Miller, Austin, De Koninck, Phillips, 
Meek, Worthen, Shumard, Hall, Lyon, Cassaday and others, 
at least so it appears to me, is the most interesting and important. It is written 
with a clearness and particularity rarely to be seen in paleontolo ics cal memoirs. 
it the opi 6 
TES eee hfe ee Me aes Pee eee 
a Bi ag 
men who have access to the magnificent cabinets of the geologists of the 
_ ern States, and also by men who habitually discuss scientific subjects with nthe 
sole objec et in view of arriving at the truth. 
