472 PALEONTOLOGY OF ILLINOIS. 



protuberant margins. Pseudo-ainbulacral areas narrow, 

 with nearly parallel sides, almost equaling the entire length 

 of the body, nearly as prominent as the slightly raised 

 margins of the radial pieces on each side; pore pieces 

 twenty-five to thirty on each side of the mesial furrow; 

 supplementary pore pieces unknown; lancet pieces appa- 

 rently riot visible externally. 



Mesial opening of the summit very small; so-called 

 ovarian apertures minute, and situated one on each side 

 of the interradial pieces ; anal opening comparatively large, 

 with very prominent margins. 



Surface of the radial plates between the pseudo-ambu- 

 lacral areas longitudinally granulo-striate, while that of the 

 interradial and anal pieces is marked in the same way 

 transversely with a downward curvature. 



Length of one of the oval specimens, 0.36 inch; breadth, 

 about 0.28 inch; breadth of pseudo-ambulacra, 0.05 inch. 

 Length of a smaller, proportionately shorter specimen, 0.28 

 inch; breadth, 0.25 inch. 



This is another species having much the general appearance of G. 

 melo, from which, however, it is at once distinguished by its compara- 

 tively much larger interradial and anal pieces, flat spaces between the 

 pseudo-ambulacra, without any furrow along the mesial suture, and its 

 more protuberant base and anal pieces. 



It is more nearly allied, however, to the last described species in 

 several of these characters, though sufficiently distinct to be readily 

 separated on comparison. For instance, its anal and iuterradial pieces 

 are nearly twice as large as in that species. Again, its base is propor- 

 tionally two or three times as large, and so protuberant as to be seen in 

 a side view, instead of being concave; while its pseudo-ambulacra! 

 areas do not extend so far down, and the little projections of the radial 

 pieces at the lower extremities of these areas point out horizontally, 

 instead of being directed nearly downward, like five little legs, upon 

 which the body stands when placed on an even surface, as in the last. 



We have seen five specimens, all of which agree in the characters 

 given. 



Locality and position Lower division of the Burlington group, at 

 Burlington, Iowa. Lower Carboniferous. No. 39G of Mr. WACIISMUTH'S 

 collection. 



