Manual of the Paleontology of the Cincinnati Group. 



139 



ambulacral pores; adambulacral plates elongated, sloping outwards so 

 that they partly overlap each other ; adambulacral ossicles contracted 

 in the middle, dilated at each end." (Can. Organic Remains, decade 

 3, P- 80.) 



1. — T. elegans S. A. Miller, 1882. 



Body deeply stellate ; rays long, slender, flexible, margined on 

 either side with a row of spines ; probable diameter from tip to tip of 

 rays one and one-quarter inches ; dorsal surface of rays rounded with 

 a single row of plates ; ventral side marked by a furrow in the center, 

 separating two series of plates or ossicles: plates slightly longer in the 

 direction of the ray than across it, breaking joints alternately in the 

 center where they are slightly contracted. (Jour. Cin. Soc. Nat. Hist., 

 vol. 5, p. 41.) 



Locality. — Waynesville, O. 



Genus 3. — PROTASTERINA Ulrich, 1878. 



Rays five, slender, flexible, and extending much beyond the 

 circular and minutely granular disc, which is provided with short, 

 slender, outwardly directed spines; inner ray pieces regularly alterna- 

 ting, of an hour glass shape, and interlocking along the median line ; 

 outer ray pieces elongated, directed obliquely outward, so as to partly 

 overlap each other ; two rows of large pores between the inner and 

 outer ray pieces, which in some species appear to have been occupied 

 by loosely-fitting, sub-pyramidal plates, some of which have a deep 

 depression in the top, as though perforated ; oral plates ten, each pair 

 formed by two of the outer ray pieces. (Jour. Cin. Soc. Nat. Hist., 

 vol, 1, p. 95.) 



I. P. FIMBRIATA Ulrich, 1878. 



Disc of medium size, circular ; dorsal surface covered with a 

 granular integument ; ventral surface with a large number of outwardly 

 directed short and slender spines ; oral plates ten, the inner edges 

 with five spines, while extending from each pair over the mouth, is a 

 bundle of rather long spines ; rays apparently very flexible, contracted 

 toward the mouth ; six series of plates on the ventral surface of each 

 ray, the two middle series alternating and interlocking along the mesial 

 line, and twice as long as wide; each contracted in the middle on the 

 inner side to admit the wide edges of the two immediately opposite, 

 forming on the outer side a pore-like impression ; four plates in each 



