BATOCRINID^. 525 



rather large, decreasing gradually in size ; disposed generally in six rows, of 

 ■which the upper ones are irregular and not readily recognized; the first plate, 

 which has the size of the first costals, suj)ports two plates in the second row, 

 and three in the succeeding ones. Anal interradius wide, the first anal plate 

 as large as the radials ; succeeded by three plates, the middle one the smallest, 

 and four or five plates in the rows above. Tegmen almost flat, its diameter 

 remarkably small, owing to the constriction at the upper regions of the dorsal 

 cup. In the casts there are no traces of disk ambvdacra, and nothing to 

 indicate the presence of orals in this species ; the whole surface is covered 

 by the impressions of small, irregular plates, surrounded by what appears to 

 represent the arm openings, which were apparently arranged in groups, 

 forming a circle around the disk. The exact number of primary arms could 

 not be ascertained from the specimens, but we have reason to believe there 

 were eight arms to the ray. Anus subcentral, apparently not large. 



Horizon and Locality. — Upper part of Niagara group, near Chicago, Ills. 



Periechocrimis infelix (Winch, and Marcy). 

 Plate L^ Figs. 2a, h, c, cl. 



1365. Meghtocrimis infelix — Wixchell and Makct ; Mem. Bost. Soc. Nat, Hist., p. 110, Plate 2, Pig. 7. 



1879. Sjn. of Saccocrimis C/irisli/i — Ball; 28tb Rep. N. Y. State Mus. Nat. Hist., p. 127. 



1881. Saccocnims infelix — S. A. Muler ; Journ. Ciuciu. Soc. Nat. Hist., Vol. LV., p. 260, Plate 6, 



Egs. 2, 2ff, h. 

 1SS5. Periechoerims infelix (?) — W. aud Sp. ; Revision Palffiocv., Part 111., p. 106. 



Syn. Saccocrimis Egani — S. A. Miller; Joiim. Ciuciii. Soc. Nat. Hist., Vol. IV., p. 173, Plate 4, 

 Figs. 4, ia. 



Smaller than the two preceding sj)ecies. Dorsal cup somewhat obconical, 

 higher than wide ; sides convex, abruptly spreading from the basals to the 

 top of the radials ; the upper regions almost cylindrical, sometimes a little 

 spreading; surface of plates slightly convex, and covered with obscure 

 radiations. 



Basals small, forming a shallow pentangular cup. Radials and costals 

 rising to three fourths the height of the calyx; the radials much wider than 

 the, first costals, about as wide as long, and the sloping upper faces almost as 

 short as the upper face ; the first costals, as a rule, a little larger than the 

 second. Distichals two, one third smaller than the preceding axillary. Pal- 

 mars two, small. Interbrachial and interdistichal areas somewhat grooved at 

 the npper ends. Interdistichals disposed in six to seven rows ; the first as 

 large as the first costals, with obtuse upper angle and long lateral faces, great- 



