92. CONTRIBUTION TO 



rate this from all other blastoids. The absence of the stem facet is a still 

 more striking feature. 



The small basal plate, pushed toward the anterior side, supports two 

 elongated radials above, and on the other side is half enveloped by the two 

 elongate radials of the posterior side. These paired radials are half the length 

 of the body and support on their long sides two elongated radials of abnormal 

 shape, and a short broad radial on their curved upper edges. This posterior 

 radial resembles the radial plate of a PlatycTinus. The normal interradials 

 are rather short, and the two adjoining the short ambulacrum are somewhat 

 narrower. 



The little projections at the lower ends of the normal ambulacra, are ex- 

 travagantly extended outward. 



The normal ambulacra are about four-fifths the entire length of the body, 

 and somewhat below the incised edges of the supporting radials. The two 

 lateral ambulacra are somewhat longer, with hardly noticeable projections be- 

 low, and not sunken below the general surface, except near the summit. 



The azygos ambulacrum is quadrangular and confined to the summit of 

 the calyx. 



The central opening is small, and there are apparently eight spiracles, but 

 this observation is not quite satisfactory, as all of the specimens seem to be 

 injured somewhat at the top. 



The specimen shown in figure 3 is much larger than the others. 



They come from the Upper Devonian, near Charlestown, Ind., and all the 

 figured specimens are in the collection of Mr. G. K. Greene. 



PENTREMITIDEA(?) DUBIA, N. Sp. (Eowley). 



Plate 30. Figs. 5, 6, 7, 11. 



The three basal plates of this little blastoid form a sharp triangular pyra- 

 mid which is more than a fourth of the entire body in depth. The radial 

 plates are nearly three-fourths of the entire body length. The interradials are 

 not visible on a side view, being minute and confined to the summit. Sharp 

 radial projections receive the distal ends of the ambulacra and extend hori- 

 zontally outward. 



The ambulacra are rather narrow and are but little below the edges of the 

 grooves in which they lie. 



Outside of the basal pyramid, the body is somewhat elliptical and circular 

 in cross section, tlie interambulacral spaces being convex, and the whole having 

 a plump appearance. 



The columnar scar is round and small. 



