586 THE CEINOIDEA CAMERATA OF NOETH AMERICA. 



AMPHORACRINUS Austin. 



1848. Austin; Quart. Journ. Geol. Soc, London, Vol. TV., p. 292. 



1855. RoEMEE ; Letlisea Geognostica (Ausg. 3), p. 249 (in part Affaricocrinus). 



1861. Hail; Boston Journ. Nat. Hist., p. 280 (in part Agaricocrimis). 



1866. Meek and Worthen ; Geol. Rep. Illinois, Vol. II., p 209 (in part Ilorymrms). 



1879. ZiTTEL; Handb. d. Palseont., Vol. I., p. 370 (subgenus of Actimcrinus). 



18S1. W. and Sp. ; Revision Palaiocr., Part 11., p. 151 (Proceed. Acad. Nat. Sci. Pbila., p. 325). 



1889. S. A. Miller ; N. Amer. Geol. and Pateont., p. 223. 



Syn. Amphora Gdmbeeland ; 1826, Reliqu. Conserv., p. 36. 



Sjn. Actinocriiius Phillips, 1836 ; Portlock, 1843 ; McCoy, 1844 ; and Hall, 1860 (Suppl. Geol. 

 Rep. Iowa). 



The rays of the Ccalyx, like those of Actinocriniis, extended outward, and 

 forming five lobes, which are distinctly separated by the plates of the inter? 

 radial areas. In Amjjlwixicrinus, however, the dorsal cup is shorter, either flat 

 or saucer-.shaped ; the proximal part of the brachial lobes projects downward, 

 hiding the whole or a part of the cup from a side view. The ventral disk also 

 is proportionally much higher, and provided with an excentric, very short 

 anal tube, while the tube of Actinocrmus is nearly central and very long. 

 In the known species there are never any radiating ridges upon the plates 

 the entire surface of the calyx presenting a rather uniform, granular appear- 

 ance, peculiar to this genus, which is difiicult to describe. Basals three, short, 

 disk-like. The rays free from the top of the second costals or first distichals, 

 whence they extend outward and downward. Arms heavy and biserial, either 

 branching or simple; in the latter case provided with lateral spines, given off 

 at intervals from opposite sides. Anal plate generally smaller than the radi- 

 als, and followed either by two or three plates, of which the middle one, 

 when present, is cuneate, and wedged in between the other two, often 

 barely touching the anal. The second row of interbrachials stands on a 

 level with the brachial lobes, and the plates are in part interambulacral. 

 Orals large, and always more or less spinous. Ambulacra apparently cov- 

 ered by perisomic plates to the base of the free rays. Column round, of 

 moderate size, and with a small, pentangular or five-rayed canal. 



Distribution. — Restricted in America, so far as known, to the Waverly 

 group and Lower Burlington limestone ; in Europe it occurs in the Carbon- 

 iferous limestones of Great Britain. Only three species are recognized by 

 us in America, and a like number is recorded from Europe. 



RemarJcs. — Cumberland, in 1826, proposed the name Anvpliora for two 

 species, which he distinguished as No. 1 and No. 2. The former, and the 



