76 
On the anterior arm of the same radius the first pinnule of 
the outer side has very much the same character as that of the 
outer side in Fig. 6, f., having only four branches or pinnules at 
the point, the first occurring on the 9th joint; the first pinnule of 
the inner side of the arm has developed into a small arm, the 
pinnules beginning to appear with the 5th joint. It presents the 
unusual feature that the three lower pinnules are all on the same, 
proximal side; after the third pinnule follow four joints without pin¬ 
nules then one with a pinnule on the distal side, whereafter the 
little arm ends in a pinnule-like point, carrying tentacles as the 
usual pinnules; also the first pinnule on this arm carries tentacles 
and has thus not the character of an oral pinnule. 
Having found this remarkable specimen, I was, of course, on 
the look out after other similar abnormalities, and I succeeded in 
finding, among several hundreds of specimens of this Crinoid five 
more showing interesting abnormalities, although none of them ap¬ 
proaches the first specimen in regard to excessive development of 
the pinnules. I shall describe briefly also these specimens. 
One of them has the first pinnule on the outer side of the 
anterior arm of left posterior radius developed into a small arm 
almost like that shown in Fig. 6, d. The three lower pinnules are 
found on the distal side, the first of them on the 6th joint; then 
follows one pinnule on the proximal side, and a pinnule-like ter- 
mination of the whole structure. The ambulacral furrow is well 
developed in the whole length of this oral pinnule. The other arms 
present no anomalous structures. 
A third specimen has the first pinnule on the outer side of 
both arms of right anterior radius dichotomously branched (Fig. 6, c.). 
The one of the anterior arm divides at the 4th, that of the post¬ 
erior arm at the 5th joint. Both branches are equally developed 
and retain their characteristic structure throughout. This case then 
represents a simple dichotomy and is of no special interest. — Three 
other specimens show simple dichotomy of one of the arms, the 
division occurring in two of the cases immediately above a syzygy. 
One of them (Fig. 6, g.) shows the interesting feature that the 
epizygal joint is divided after a longitudinal line. In the other 
case one of the branches begins with a syzygy. The third specimen 
