298 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
thin, thread-like, with closely packed pinnules. Regular interbrachials: 
1, 2, 3, and others above, which gradually intermingle with the interambu- 
lacrals. The first interbrachial of the anal side is somewhat the largest, and 
is followed by three plates in the second row, which form an arch, and by 
four pieces in the third and fourth rows. Ventral disk low, depressed-pyra- 
midal, apparently surmounted by a subcentral anal tube; the plates more 
or less uniform, of about medium size, and somewhat convex. 
Forizon and Locality. —In a limestone layer, six inches in thickness, 
above the base of the Black Slates, Bainbridge, Ross Co., O., and at Canan- 
daigua, N. Y., in rock of about the same age. 
Type in the Ohio State collection, Columbus. 
Remarks. — Prof. J. M. Clarke of Albany had the kindness to send us 
gulta-percha casts of the types of Melocrinus Clarkei Williams, which we 
regard as identical with MV. bainbridgensis. 
Melocrinus gracilis W. and Sp. (nov. spec.). 
Plate XXII, Fig. 5. 
A rather small species, of the type of Melocrinus (Ctenocrinus) stellaris 
Roemer. Dorsal cup obpyramidal; the radials and costals strongly curved 
so as to form broad, very conspicuous longitudinal ridges with a small 
tubercle at the centre of each plate, those of the axillaries being the longest 
and sharpest. Interbrachial spaces depressed, giving to the section across 
the second costals a sharply pentangular, somewhat stelliform outline. 
Basal cup low, broadly truncate at the bottom, its lower edges slightly 
projecting beyond the column; the upper angles turned abruptly upwards. 
Radials and costals nearly equal in size, wider than long, but the curvature 
makes them appear to be longer than wide. Distichals 2 x 10, rounded like 
arm plates; short, transversely arranged, those of the same ray separated by 
one or two minute interdistichals, which rest within the bottom of a shallow 
pit. The arm trunks bend outward, are heavy, and composed of two rows 
of short pieces. The arrangement of the arms cannot be ascertained, as in 
the single specimen the trunks are preserved only to the fourth plates, and 
of the arms only fragments of a single one. Interbrachials numerous, 
slightly decreasing in size upward; arranged: 1, 2, 3, 3, etc. They are 
somewhat convex and ornamented with obscure radiating ridges, which con- 
nect with the interambulacral plates. Ventral disk elevated, and, so far as 
