HAO PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
In a genus in which the distichal “ axillary ” commonly bears a 
pinnule instead of a second arm, one might expect to find individuals 
in which the costal axillary was similarly altered; Mr. Springer 
(Plate vi, fig. 8) figures a case in which the second costal bears a 
pinnule; the two distichals are present as usual, the second bearing 
a pinnule on the opposite side from that of the second costal. 
A rather peculiar condition is figured (Plate v1, fig. 7) where ap- 
parently the distichal pinnule is on the inside instead of the outside 
of the arm; in other words, the two offshoots from the second dis- 
tichal, the arm and the pinnule, have exchanged places; this speci- 
men is further abnormal in lacking the first distichal. 
The distichal series of two joints of which the second is not an 
axillary, but bears a pinnule, like the second costal in Hudiocrinus, 
would seem to be a retrogressive character, as in all other comatulids 
the second distichal (or fourth when doubled—i. e., (8+4)) 1s : 
axillary, just as the simple pinnule-bearing second costal of A’udio- 
crinus appears to be retrogressive; we should, therefore, expect that 
in the young Uintacrinus the second costal would appear more like 
an axillary than in the adult. On consulting Plate m, fig. 4, and 
Plate vi, fig. 4, we find this to be the case; the second distichal has 
distinctly the appearance of an axillary joint. 
