42 



Compariu^- tliis sp(>pies with Ihiiiicriiius n\a^nt jiritft, it will be 

 fomul to be proportionally iiuicli more expanded, and consequently 

 the first radials are imieh wiilei- in jiioportiou to their length, 

 and the facets for the second radials are larger and face nearer 

 horizontally. The plates, too, are much more convex and deeper 

 sunk at the angles, and in these respects, it has some resemblance 

 to B. herculeus. It cannot be mistaken for either of those species 

 nor for any other hitherto described. 



Found in the Keokuk Group, in Tennessee, and now in the 

 collection of Wm. F. E. Gnrley. 



Family SYNBATHOCRINID.E. 



SYNB.4TH0CRINUS ANGULARIS, n. sp. 



Plate IV. Fig. ,>, lateral vieir showing the greater diameter : 

 Fig. Jf., azygous side view. 



Species below medium size. Plates angular. Arms very much 

 constricted at the top of the second radials. Our specimen appears 

 to be in its normal shape, but the calyx and arms are compressed 

 laterally, so the diameter is nearly twice as great one way as the 

 other, while the column is perfectly round and composed of rather 

 long plates. Surface of all the plates granular. 



The basals have a pentagonal form externally, the two shorter 

 sides being the anterior and posterior ones, the longer side being 

 the right lateral one when facing the azygous area, and the other 

 two being the left lateral ones. This gives to the little cup, formed 

 by the basal plates, a greater diameter antero-posteriorly than lat- 

 erally and shows the calyx is in its normal condition, and not flat- 

 tened by pressure. First radials of unequal width, and each one 

 longer than wide. Each one is beveled from the central part 

 toward the sutures, which makes each one subpyramidal. They are 

 truncated the entire width above for the second radials, and in ad- 

 dition to both plates being beveled to the suture, the suture is 

 slightly gaping. The second plates are rather longer than wide, 

 quadrangular, taper a little* upward to meet the constriction of the 

 arms at the commencement of tiie third plate, or, in other words, 

 tile dij) in toward the constriction. They, and all the other plates 

 of the arms are beveled laterally to the sutui-es so that the central 

 part of each arm is one continuous angular ridge. While the calyx 



