, BATOCKINID^. 425 



twice as long as wide. Interbracbials two or three on the regular sides 

 three to six on the posterior; arched bj the paluiars. Anal plate a little 

 higher than the radials, occasionally followed by two plates in the second 

 range in place of three ; the second anal, although present, not in contact 

 with the first. Ventral disk highly convex, slightly conical, the plates 

 nodose and of irregular arrangement. Anal tube slender, almost central. 

 Cohiinn thin; composed of larger and smaller joints. 



Horizon and Locality. — Warsaw limestone, near Hiintsville, Ala., Tate- 

 ville, Pulaski Co., Ky., Boonville, Mo., and Lee Co., Va. 



The type specimen, which is from Union Co., Ills., is in the (Worthen) 

 Illinois State collection. 



Eemarhs. — This species is very interesting as having sometimes in the 

 posterior interradius but two plates above the anal piece, in which it shows 

 a tendency toward the Actinocrinidse. It also has a wide -geographical 

 range, and may be regarded as one of the leading forms of the lower part of 

 the Warsaw limestone, but occurs already in the Upper Keokuk beds. 



Actinocrinus CaroU Hall is very possibly identical with this species, but 

 the type in the Illinois State collection at Springfield is too imperfect for 

 accurate definition. 



Dizygocrinus unionensis, var. divalis (S. A. Millek). 

 FMe XXXV. Figs, n, 22, S3, U- 



1892. Batocrmm divalis — S. A. Millek; AdT. Sheets IStli Rep. Geol. Surv. Missouri, p. 22, Plate III., 

 Figs. 6 and 7. 



A little larger than the typical form; the dorsal cup more expanded, the 

 ventral disk somewhat more conical, but so closely resembling it in its general 

 habitus, in the form and arrangement of the plates and their ornamentation, 

 that the two cannot be distinguished unless the arms are preserved. Arms 

 double from their origin, thirty-six in fully developed specimens, rather stout 

 and densely crowded. Arm joints of more than medium length. At the 

 four regular sides, the interbracbials consist of three to four pieces, at the 

 anal side of from six to eight. 



Horizon and Locality. — Associated with the preceding form at Boonville, 

 Mo., and at Huntsville, Ala. 



Types in the collection of Mr. S. A. Miller. 



Remarks. — That we have here a mere variety of Dizygocrinus unionensis, 



