BATOCRINID&. O47 
area, and in the form and position of the anus, in all of which it resembles 
Aorocrinus. liyon’s type is in an abnormal condition, and we have figured 
other specimens in place of it. It has but four arm-bearing rays, the postero- 
lateral ray apparently having been injured during the life of the Crinoid, 
and the space from the first axillary up being filled by abnormal growth. 
Besides the left antero-lateral ray has four in place of two primary arms. 
Whether the arms of this species are branching is not known. 
GENNA:OCRINUS W. and Sp. 
1881. W. and Sp.; Revision Paleocr., Part II., p. 160 (Proceed. Acad. Nat. Sci. Phila., p. 334). 
1891. 8. A. Mintzer; North Amer. Geol. and Paleont., p. 247. 
Syn. detinocrinus (im part). 
Calyx distinctly lobed ; the interradial spaces extremely wide, and deeply 
indented at the arm regions. Plates thin, their surfaces ornamented with 
radiating striz. Basals three, small; the axial canal large and pentalobate. 
Radials and costals of similar form, but decreasing in size upwards; the first 
costal hexagonal, the second heptagonal. The branching of the rays above 
the distichals is from alternate sides, the second plate of the two main divi- 
sions giving off at one side an arm, at the other brachials of a higher order, 
the last axillary supporting two arms. The different rays have the same 
number of arms, which is eight, so far as observed. Interbrachials quite 
numerous, and the upper ones in contact with the interambulacrals; the first 
is followed by two or three in the second row — which are larger than usual 
in the Batocrinidze — and these by three or four smaller ones. The first 
anal plate supports a second, which has an interbrachial at each side, and 
there are several rows of four or more plates above. The tegmen is com- 
posed of rather small plates, and rises but little above the dorsal cup; the 
surface is undulated, being grooved and indented interradially, and distinctly 
raised all along the food grooves, which are covered by two rows of alternate 
pieces. Orals proportionally small, the posterior one a little the largest. 
There is no anal tube, the anus being represented by a small, excentric 
opening, passing out directly through the tegmen. 
Distribution. — Restricted to the Hamilton group of America. 
Type of the genus. — Genneocrinus kentuckiensis (Shumard). 
Lemarks. —'This genus, in the branching of the rays, grouping of the 
arms, form of the tegmen, and in the simplicity and position of the anus, 
