38 



Basals form a uarrow peutagoual rim almost obscured by the 

 coluinn. Hubradials abruptly bent upward aud iuto the basal 

 concavity, at about the middle part, about as wide as loug. The 

 one on tlie right of the azygous area heptagonal and broadly 

 truncated for the first radial, the next one to the right hexagonal. 

 First I'adials twice or more than twice as wide as high, peutagoual, 

 truncated the entire width above and separated from the second 

 radials by a gaping suture. Second radials larger than the first, 

 about twice as wide as high, pentagonal, prominent almost nodose 

 at the superior angle, and supporting on each ujiper sloping side 

 the secondary radials. There are six secondary radials in each 

 arm shown by our specimen, four of them are short plates with 

 transverse sutures, the first one is the larger one and the last 

 is pentagonal aud supports upon each of the upper sloping sides 

 the tertiary radials. One of the arms does not again bifurcate 

 and consists of short tlatteued quadrangular plates. The other 

 arm bifurcates again on the eighth plate and the arm adjoining 

 the azygous side again bifurcates, and so does the corresponding 

 arm in the other ray, which gives us seven arms to each of these 

 rays. 



The first azygous plate is pentagonal, abuts upon two sub- 

 radials aud the first radial on the right, and supports two inter- 

 radials in the second range, one of which truncates a subradial- 

 There are two iuterradials in the third range, beyond which they 

 are not shown in our specimen. 



It is not necessary to compare this species with any other for 

 the purpose of distinguishing it. 



Found in the Keokuk Group, at Salem, Indiana, and now in 

 the collection of Wm. F. E. Gurley. 



ZEACRINUS CYLINDBICUS, n. sp. 



Plate ITI, Fig. 19, a large specimen compressed aiiiero-pos- 

 feriorly showing azygous side; Fig. 20, a sindller 

 specimen compressed laterally showing azy- 

 gous side ; Fig, 21 , opposite vieir of sa.m e. 



This species is rather large and very long. The body is sub- 

 cylindrical, though constricted above the calyx, slightly fusiform 

 in the middle part, aud slowly tapering above. 



