102 
pieces qui rcnclavent et qui, ii cet efTet, out cliacune ime partie de I’lm de 
leur bords lateraux uii pen ecliancree.’ ^ These are, of course, the first and 
second radials {auctorum), or radials and eostals as wo now call them. 
“ Again, in Wachsmnth and Springer’s last paper on the perisomic 
plates ot‘ the Crinoids, they refer to the plate x as resting on the posterior 
hasal, and support ing a ‘ quite capacious ’ ventral tnhe. Tliis is not the case 
in the type of Graphiocrinns. 
I do not think that any importance, from a generic point of view, is 
to he attached to the extent to which the nnder-hasals are visible beyond the 
stem articulation. Neither can anything be made of the fact that Phialo- 
crinus patens has two eostals, while the American species resemble Graphio- 
crinus in liaving but one; for Hall says that there may he two in the anterior 
ray of G raphiocrinns tortuosiis, which seems to have the anal structure of 
jPhialocrinns, while Trantschold says that there may sometimes he only one 
costal in the latter genus. 
“ Miller and Gurley have recently described a new genus, ^T!siocrinus, 
Avhieh has a dicyclic and horvl-shaped calyx, with the posterior hasal truncated 
for the reception of an anal plate and two costal plates. I cannot see in what 
respect this genus dilfers from Trantschold’s Th'ialocrinns, though the 
authors think that ‘ probably a nerv family should he defined for its recep- 
tion.’'^ They describe three species, each with two eostals, which thus 
resemhlc the Hnssian rather than the other American species of the genus. 
“ Bursacrinus^ M. and M ., to which AVachsmuth and Springer have 
united Si/ni/pJiocrint/s, Trantschold, and I think rightly so, has the same 
arrangement on the anal side as Bhialocrinns, hut dilfers in having a more 
funnel-shaped cup, and more branching arms. The type species, B. IVach- 
smnthi, has six to eight distichals, hut in B. cornnlus there are hut two. 
In either case, however, there are twenty arms, while Bhialocrinns, so far as 
known, has hut ten, and not always that, for there is no costal axillary on 
the anterior ray of P. rmlisB 
Bhialocrinns, therefore, as now understood by us, is distinguished 
from G raphiocrinns, De Koninck, by the position of its anal plate, resting on 
the truncated ventral edge of the posterior hasal, and thus entering the ring 
■ Rech. Crinoides Terr. Carb. Belgi(|ue, 1853, p. 110. 
* Jouni. Cincinnati Soc. Nat. Hist., 1890, XIII, p. 15. 
