1881.] Geology ana Palaontology. | 1021 _ 
crowded small fossa, giving a delicate reticulate relief. Length 
of an intercentrum, .013; width of do.,.014; width of the sum- 
mit of a neural spine, .020; length of do., .o14; width of a sec- 
ond do, .025; length of do., 015; width of a third (two unite), 
.034; length of do., .039. The reference of this species is pro- 
visional only. It is much larger than the Z. serratus, D. 
Cope. 
Published November 29, 1881 
