PALEONTOLOGIC CONTRIBUTIONS 65 



ambulacral and thereby delimits the subquadrangular lateral depres- 

 sion in which the ambulacral pore and the podial cup are found. 

 To each column of side plates are attached a series of large, wedge- 

 shaped spines, whose bases are widened laterally and saddle- 

 shaped, riding on the side plates ; and at the same time extended 

 into a process proximally (see pi. 22, fig. 3; pi. 23, fig. 5) 

 by which they interlock. The spines were concave or flat on the 

 proximal side and somewhat convex on the other. Their distal 

 portion was apparently hollow (see pi. 22, fig. 5; pi. 23, fig. 6) 

 the distal extremity truncate with indications of a cuplike depression 

 in some specimens. Both the base and the end of the spines are 

 furnished with dense masses of fine club-shaped bristles or spines, 

 apparently paxillae (see pi. 22, fig. i; pi. 23, figs." 1, 6, 7). The 

 lateral spines reach 3 to 4 mm in length, the secondary spines, I to 

 2 mm. The abactinal area of the disk is covered by irregular larger 

 plates (see pi. 22, fig. 2). The oral armature consists of heavy 

 arched frames, bearing apparently thick teeth. The details of the 

 armature are not clearly recognized, owing to the circumstance that 

 the ossicles were only seen from the dorsal side. 



The disk and both actinal and abactinal sides of the rays are 

 covered by a thick integument (see pi. 22, figs. 7 and 8 ; pi. 23, fig. 2) 

 which on the abactinal side is densely set with nonarticulate spines 

 (see pi. 23, fig. 1). On the ventral side the integument leaves in 

 the median line a series of slits open with thickened margins (see 

 pi. 22, figs. 7 and 8) and what may have been rows of pores (podial 

 pores?) or spine-bases. The bases of the large lateral spines were 

 apparently also covered by this integument (see pi. 22, fig. 7). 



Horizon and locality. Naples beds (West Hill flags), gully of 

 Italy Hollow, Yates county, X. Y. and Deyo Basin near Naples, 

 N. Y. 



Remarks. The material of this species consists of five drawers, 

 all taken from two adjoining layers. The species must have been 

 very abundant at the site for we counted over twenty fragmentary 

 rays on one slab not one-half of a square foot in size ; but owing 

 to its remarkable brittleness it is impossible to obtain entire speci- 

 mens. Many of the broken rays are rolled up into circles. The 

 strange aspect of the rays is due to the strong rows of lateral 

 spines and the spinous integument. The dense bundles of large 

 paxillae on the ends of the spines must have still increased the 

 peculiar aspect of the form (see restoration, _ plate 21). A similar 

 integument is also known from other auluroids, as is evident from 

 Stiirtz's work on the Bundenbach Stelleroidea. 

 3 



