BATOCRINID^. 469 



those of the radial series formed into conspicuous, angular, transverse nodes, 

 the interradial plates into large rounded or pointed tubercles. 



Base small, short, hexangular in outline, slightly notched at the suture 

 lines, excavated at the bottom to enclose one or two joints of the column. 

 Eadials a little wider than long, the length of the lateral margins about equal 

 to the width of the upper and lower faces ; the upper sloping faces small. 

 The nodes of the plates directed obliquely downward, and their extremities 

 reaching the level of the lower face of the basals. First costals short, quad- 

 rangular, more than twice as wide as long. Second costals a little longer, 

 pentangular or subtriangular, their lateral faces short. Distichals larger than 

 the costals, there being two in the three anterior rays, which directly support 

 the arms. In both posterior rays, the division facing the anal interradius has 

 but one distichal, followed by two series of two palmars ; while the other 

 division has two distichals and no palmars. Arm bases projecting, indented 

 at the sides, the interspaces between the rays wider than between their sub- 

 divisions, and the space between the posterior rays still wider. Arm facets 

 large and lunate, the ambulacral openings facing outward. Arms in twelve 

 pairs, long, stout, infolding, rounded at their bases, flattened and wider in the 

 upper portions, and composed of two series of moderately short j)ieces, which 

 grow longer upward. Some of these pieces are produced at the outer side 

 into small nodes, which higher up in the arms turn into short, quite conspicu- 

 ous spines. Near the calyx only every third plate bears a node, but through- 

 out the flattened portions of the arms every other plate. Interbrachials three ; 

 the two upper ones elongate, resting between the arm regions. The plates 

 of the posterior interradius consist of five or six large anal jDlates longitudi- 

 nally arranged, of which the two upper take part in the ventral disk ; and 

 two interbrachials, one at each side of the second anal. The u^jper anal 

 plate supports a number of small, irregular pieces, forming together a turgid 

 elongate area, which near its upper extremity contains the anal opening. 

 Plates of the ventral disk higlily convex, sometimes conical, covered in well 

 preserved specimens by small vermicular granules, except those surrounding 

 the anus, which are perfectly smooth and almost flat. Orals large ; the pos- 

 terior one central, and extended into a long, slender spine. The food 

 grooves are covered by three large plates of a first and second order, of 

 which sometimes the primary plate in one or both posterior rays is spinous, 

 while in most specimens these plates are no more tumid than the three others. 

 Approaching the arm openings there are two secondary radial plates, which 



