5 el 
i 
- r 
a aS Len Ay Te 
048 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
closely resembles Physetocrinus, but that, having no anal plate in the first 
interbrachial row, is an Actinocrinoid. 
Genneocrinus kentuckiensis (Suumarp). 
Pigte XXXIV, Figs. AL, 12, £3. 
1866. Actinocrinus kentuckiensis —SuuMaRD; Trans. Acad. Sci. St. Louis, Vol. IT., p. 345. 
1881. Genneocrinus kentuckiensis — W. and Sr.; Revision Paleeocr., Part IL, p. 161. 
Syn. <Aetinocrinus cornigerus Lion and Cassepay, 1859 (not Haun, 1858); Amer. Journ. Sci. 
(a. series), Vol. XXVIIL., p. 238. 
Syn. Actinocrinus nyssa Hatt, 1862; 15th Rep. N. Y. State Cab. Albany, p. 129. 
Of medium size. Calyx wider than high, decidedly lobed at the arm 
regions, and the arms given off in clusters. Dorsal cup semiglobose; the 
surface covered with well-defined stria proceeding from the centre of the 
plates to their margins. There is a ridge to each face of the plates, and 
another to each angle, which meet with similar ridges from adjoining plates, 
and form with them all sorts of triangles. The ridges following the rays 
increase in prominence as they approach the distichals, and attain at the 
arm bases almost the width of the arms. 
Basals very short, slightly projecting laterally, forming a thin trilobate 
rim, which is flat at the bottom. Radials and costals as long as wide, de- 
creasing rapidly in size upward; the-second costals less than half the size of 
the radials. Distichals 2 X 10, comparatively small, wider than long; the 
second ones axillary, supporting 2 X 4 palmars, of which the two of the 
outer sides are followed by one arm, the two inner ones by two arms, the first 
plate taking part m the calyx. There are eight arms to each ray, in close 
contact; while those of different rays are far apart. Whether there is any 
branching in the free arms is not known. Interbrachials: 1, 2, 4 (some- 
times 1, 3, 4); succeeded by one or two rows of smaller pieces, of which the 
upper interlock with the interambulacral plates. The first anal piece sup- 
ports three large plates in the first row, five in the second, and five or more 
in the third. Interdistichals three in two rows. Ventral disk depressed- 
convex; the interambulacral plates together with the interbrachials form 
wide and deep recesses around the calyx, while the radial portions project 
conspicuously upward and outward. All plates of the tezemen of nearly uni- 
form size, and each one covered with a small central tubercle. Orals com- 
paratively small, even the posterior one, which is central, being but little 
larger than the other plates. Ambulacra covered by two rows of alternating 
