28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



Catillocrinus carpenter! (Wachsmuth) 



Plate 4, figs. 1-18 

 Allagecrmus carpcnteri, Geol. Surv., Ill, VII, 1882, p. 341, pi. 29, fig. 14. 



The smallest species, being the end of a degenerative series ; repre- 

 sented by twenty specimens from three dififerent localities, uniformly 

 v^ithin the size limits given below. Cup relatively higher and less 

 spreading than in the other species. No IBB. BB about one-third 

 the height of dorsal cup, rising about equally all around ; divided into 

 three unequal plates by sutures under r. post., ant., and 1. post. RR 

 in several specimens, a single suture distinctly seen in several and 

 none at all in some. Form and proportions of RR different from 

 those of all preceding species ; r. ant. R rectilinear and much larger, 

 bearing 3 to 5 arms ; 1. ant. R narrower, and the two larger RR 

 occupying but little over half the circumference of the cup at upper 

 edge; r. post. R has no raised process, but first tube plate rests 

 directly upon it at the level of the arm bases, without any separate 

 anal plate. Arms very slender, mostly about .55 mm. in width, but in 

 smaller specimens some arms may be stouter than others, especially 

 the single arms on r. post, and 1. ant. RR. Anal tube 25 to 30 times 

 the height of dorsal cup. 



Diam. 2.5-4.7 mm. ; height 2-3 mm. ; arms 13-24. 



Mississippian. Lower part of Chester (Kaskaskia) ; Monroe 

 County, Illinois, Owen County, Indiana, and Huntsville, Alabama. 



This species, on the eve of extinction of the genus, shows a marked 

 departure from its characters in the relative proportions of the 

 radial plates. The two larger RR are relatively smaller, r. ant. R 

 has lost the curve at the right side, and has become almost as large 

 as ant. R, bearing 3 to 5 arms instead of only one as in other species. 

 Ant. and 1. post. RR lack the great increase in width at the upper side, 

 and in consequence the upward expansion of the cup is less. These 

 characters are constant in eight specimens, from the two principal 

 areas, in which I was able to free the cup from the matrix sufficiently 

 for accurate measurements. The species also, in common with C. 

 hradleyi, departs from the others in the structure of the anal side. 



PARACATILLOCRINUS Wanner 



Plate 5, figs. 22, 23, 24 

 Permischen Echinodermen von Timor, I, 1916, p. 6 



General form of calyx similar to that of Catillocrinus. Base form- 

 ing a low disk, composed, so far as known, of two basal plates, or 



