1'J2 PROCEEDINGS OF THE ACADEMY OP [1886. 



the attachment of the column ; suture lines well defined. Basals 

 large ; generally as high or higher than wide ; three of them equal, 

 hexagonal ; the two adjoining the azygous side heptagonal, larger 

 and of a different form. 



Radials all pentagonal ; the lateral faces often so short as to 

 give to the plates a trigonal outline ; their outer faces abruptly 

 depressed or rounded off toward the brachials ; upper side straight, 

 facing upward ; articular ridge well developed and occupying the 

 full width of the plate. The right posterior radial narrower than 

 the others, its lower left side disturbed by the azj-gous piece. The 

 azygous plate is very large, placed in a sloping position, its two 

 lower sides resting between two basals, its left side against the 

 adjoining radial. The small truncate upper side supports the first 

 plate of the ventral sac, the right side faces the anal plate, which 

 is always considerably smaller, and extends beyond the limits of 

 the radials. Brachials one or two ; short ; laterally touching their 

 fellows of adjoining rays. Arms 5 to 10 or more ; heavy, composed 

 of short quadrangular joints, which change into cuneate pieces 

 and in some species interlock. Arm furrows wide ; pinnules 

 strong. Articulation between radials and brachials and between 

 the lower arm joints by transverse ridges and fossse. 



Ventral sac imperfectly known, but evidently short. Column 

 small, circular ; axial canal minute. 



Geological Position, etc. Gromyocrinus is found in the upper 

 portion of the Subcarboniferous of Russia, England, Scotland, 

 Belgium, and of the United States. 



We place here the following species : 



1867. Gromyocrinus geminatus Trautschold. Referred by us, Rev., i, p. 138, to 

 Eupachycrinus. 



*1873. C. globosus (Worthen), Agassizocrinus globosus, Geol. Rep. Illinois, vol. v, 

 p. 557, PI. 21, fig. 12. Kaskaskia gr. Chester, Illinois. 



*1858. C. globularis (De Koninck), Hydreionocrinus (?) globularis, Memoirs de 

 Paleont., p. 21, PI. 2, figs. 1-4. Referred by us. Rev. i, p. 138, to Eupachy- 

 crinus. Upper part of Subcarboniferous. Near Glasgow, Scotland. 



*1849. C. nuciformis (McCoy), Poteriocrinus nuciformis, Ann. and Mag. Nat. Hist. 

 (Ser. ii), not P. nuciformis, Goldfuss (Fischer); also 1854, Contrib. Brit. 

 Palaeont. by Sedgwick, p. 116. Subcarboniferous. Derbyshire, England. 



. 1879. C. ornatus Trautschold. Referred by us, Rev., i. p. 138, to Eupachycrinus. 



*1867. C. papillatus (Worthen), Agassizocrinus papillatus, Bull., i. 111. St. Mus. 

 Nat. Hist., p. 36; also Geol. Rep. 111., vii, PI. 29, fig. 17. Kaskaskia gr. 

 Monroe Co., 111. 



