98 The American Geologist. August, 1902. 
NOTICE OF A NEW COMATULA FROM THE 
FLORIDA REEFS. 
By Frank Springer. East Las Vegas, N. M. 
Among the fine collections made by the Bahama Expedi- 
tion of the State University of Iowa in 1893, under the di- 
rection of Prof. C. C. Nutting, there are some specimens of 
a somewhat remarkal^le form of the comatulid genus Actin- 
oinctra, which were courteously placed in my hands for de- 
scription. They were found at the Dry Tortugas, living at a 
depth of three feet. The form seems to differ decidedly from 
all other described species, and is of such special interest that 
it has been thought best to give a preliminary notice of the 
occurrence, in advance of a more detailed account now in pre- 
paration, which will appear in the Natural History Bulletin of 
the State University of Iowa. The species is large, — having 
a spread of about 2"/ cm.. — with the marginal mouth, central 
anal tube, and combed pinnules characteristic of the genus. 
It belongs to the group Fimbriata, which are characterized 
by having the first syzygy in the arms between the second and 
third brachial. But this differs from the other species of that 
group, and from all others of the genus as well, by having a 
calcified ambulacral skeleton composed of alternating covering- 
plates in the arms, and to some extent in the pinnules. The 
absence of plated ambulacra has been regarded as one of the 
peculiar characters of the genus Actiiiouietra, whereby it was 
sharply separated from Antcdon and the Pentacrinidae, and 
in fact from all other crinoids, recent and fossil, except the 
Cretaceous genus Uintacrinns. The occurrence of these spec- 
imens, living in the shallowest water yet recorded for any crin- 
oid, and possessing all the characters of the genus in a marked 
degree, with this important exception, is a fact of much inter- 
est to students of the group. I have proposed for the species 
the name Actinomctva iowciisis. 
