PLATE I— Continued. 

 Retiolites venosus, Hall. 



(Palreontology of New York, Vol. ii, page 40.) 

 Figures enlarged to nine diameters. 

 Fig. 20. The exterior of the convex? side, showing the external axis and cell partitions, with 

 the intermediate reticulate texture. 

 " 21. Another view, apparently from the interior, showing an undulating or zigzag axis, with 

 cylindrical processes extending to the margins, and short, apparently broken, pro- 

 cesses directed obliquely upwards. The reticulatctexture is not essentially different 

 from that of the other side. 



