34 MESOZOIC ECHINODERMATA OF THE UNITED STATES. [bull. 97. 



ites armigery a name which he stated he des^ired substituted for G. 

 splemlens. Gabb, in his Catalogue of the Invertebrate Fossils of the 

 Cretaceous Formation of the United States, employs both names, mis- 

 taking them for independent species, althongli C. S2)Ien(1cns is referred 

 to as C. fiplendeus. The specimens examined by the writer are chiefly 

 detached plates, and in no instance is the entire test preserved, as in 

 the figure given by Morton. Two entire, or nearly entire, interambu- 

 lacral areas, with part or all of the adjoining ambulacra, are among this 

 material (PL vi, Fig. Sa). In these specimens the oral side is slightly 

 more depressed than the aboral, although not to the extent exhibited 

 in Morton's figure. The ambulaeral areas, which are narrow and flex- 

 uous, have, between the poriferous avenues, fonr granules. In the 

 center of each column of plates these granules are approximately of 

 equal size, the outer rows slightly larger, but toAvard the disk or toward 

 the mouth opening the inner rows rapidly diminish in size and finally 

 disappear. The pores are oval in shape, with funnel-like openings ex- 

 teriorly. Each row of pores is separated from that which accompanies 

 it in the same avenue by a row of imi)erfectly defined granules that 

 form an undulating ridge (PI. vi. Fig. '6c). 



The interambulacral areas are very wide and bear large tubercles, 

 each of which covers the greater portion of its respective j)late (PI. vi. 

 Fig: 3h). Upon the larger plates, in the center of each column, the are- 

 olas are circular, but become somewhat oval toward both disk and mouth 

 opening. The outer edge of each areola is surrounded by a circle of 

 large granules that give it a crenulated appearance. The areola rises 

 from its depressed margin, gradually at first, then rapidly, to the boss, 

 which reaches a marked elevation above the general level of the plate. 

 The boss is of moderate width and smooth. From its center rises the 

 unimelon, which is small, perforated, and slightly flattened upon the 

 upper surface (PI. vi. Fig. '3d). The miliary space is covered by small 

 granules, that are most numerously developed along the median line of 

 the interambulacra. 



None of the specimens afford the apical disk. Strong auriculae show 

 the presence of powerful jaws. 



The s])ines are slender, elongated, cylindrical, with longitudinal, ser^ 

 rated ribs that gradually become obsolete toward the base (PI. vi, 

 Fig. 3c). The collar is short and finely striated longitudinally (PI. Vi, 

 Fig. 3/). The acetabulum is bordered by a smooth margin and is per- 

 forated in the center (PI. vi, Fig. 3^). 



Belated /onus. — In many ])articulars Cidaris splendens (Morton) shows 

 points of comparison with C. serrata Desor of the European Cretaceous, 

 but the American species differs from it in its smaller miliary areas and 

 higher areolas, and also in the presence of only four rows of granules 

 between the poriferous avenues. 



Locality and geological horizon. — This si^ecies is reported by IVIorton 

 from Timber creek, New Jersey, which establishes the horizon as that 



