086 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
AMPHORACRINUS Austin. 
1848. Austin; Quart. Journ. Geol. Soc., London, Vol. IV., p. 292. 
1855. Rormer; Letha Geognostica (Ausg. 3), p. 249 (in part Agaricocrinus). 
1861. Hat; Boston Journ. Nat. Hist., p. 280 (in part Agaricocrinus). 
1866. Mux and WortHsy; Geol. Rep. Illinois, Vol. I., p 209 (in part Dorycrinus). 
1879. Zirren; Handb. d. Paleont., Vol. I., p. 370 (subgenus of Actinocrinus) . 
1881. W. and Sp.; Revision Paleocr., Part II., p. 151 (Proceed. Acad. Nat. Sci. Phila., p. 825). 
1889. §. A. Mizzer; N. Amer. Geol. and Paleont., p. 223. 
Syn. dmphora CUMBERLAND ; 1826, Reliqu. Conserv., p. 36. 
Syn. Actinocrinus Putters, 1836; Portlock, 1843; McCoy, 1844; and Hall, 1860 (Suppl. Geol. 
Rep. Iowa). 
The rays of the calyx, like those of Actinocrinus, extended outward, and 
forming five lobes, which are distinctly separated by the plates of the inter- 
radial areas. In Amphoracrinus, 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 Actinocrinus 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 difficult 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. 
Remarks. — Cumberland, in 1826, proposed the name Amphora for two 
species, which he distinguished as No. 1 and No. 2. The former, and the 
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