442 THE CEINOIDEA CAMERATA OF NORTH AMERICA. 



are covered with conspicuous, transversely curved prominences, which are 

 studded with two or three irregular nodes. First costals considerably 

 smaller than the radials; the second smaller than the first, in some speci- 

 mens pentagonal, in others trigonal. Distichals 2X2, larger than the cos- 

 tals, especially the upper or axillary ones, which are almost as wide as the 

 radials. Palmars 2X4, larger than the distichals. They support the arms 

 invariably in thre.e of the rays, but in the two posterior rays the second 

 plate adjoining the anal side is frequently axillary and followed by postpal- 

 mars. The distichals are not placed on a level with their fellows of the same 

 ray, but are alternately arranged, and the same is the case with the two 

 inner rows of palmars ; the arm-bearing plates being placed horizontally. 

 The brachials throughout the calyx are covered with elongate elevations, and 

 these again by a row of small nodes. Arms twenty to twenty-two ; their 

 structure unknown. Interbrachials : 1, 2, 1, and 2 between the arms; 

 the first wider than long, its node transversely elongate ; the two of the 

 second range longer than wide, and the nodes disposed longitudinally. 

 The anal plate, which is longer than the radials, followed by three plates 

 — the two at the sides wider than the middle one — and by three irregular 

 smaller pieces, which in turn support several rows of elongate interambula- 

 crals. The plates of the tegmen increase in size as they approach the middle ; 

 they are heavy, proportionally large, and the centre of .each is crowned with 

 a small tabercle. The anal tube is almost central, stout, and apparently 

 long. 



Horizon and Locality. — Keokuk group ; Button Mould Knob, seven miles 

 from Louisville, Ky. 



Types in the Yandell collection at Louisville, Ky. 



Lobocrinus longirostris (Hall). 

 PlaU XXVIII. Figs. la-e. 



1838, JcHiiocrinus longirostris — RkT.L; Geol. Rep. Iowa, Vol. I., Part II., p. 589, Plate 11, Pigs, if, d, 



and 3. 

 1873. Batocriims longirostris — Meek and Worthen ; Geol. Rep. Illinois, Vol. V., p. 367. 

 18S1. Batocrinus longisrostris — W. and Sp. ; Rerision Pat-cocr., Part II., p. IR/. 



Syn. Batocrinus cassedai/aniis — Meek and Woethen; Geol. Rep. Illinois, Vol. V., p. 370, 

 Plate 5, Pigs, la, b. 



Of medium size. Calyx ovate, higher than wide ; the dorsal cup higher 

 than the ventral disk ; the arm bases a little projecting. Plates more or less 



