Apr. 1899. PALEONTOLOGY OF UPPER CRETACEOUS SERIES—LOGAN, 211 
is oval in form with a smooth periphery; it is turned inward toward 
the coil of the shell. © 
‘¢Septa are provided with moderately broad lobes and sinuses. 
The siphonal lobe is longer than wide, and bears two rather promi- 
nent lateral branches, each of which is unequally bifid, and digitate. 
The first lateral sinus 1s about the size of the siphonal lobe and has 
approximately the same width at the base; it is divided at its 
extremity into two unequal lobes both of which are bifid, the one 
nearest the siphonal lobe having its lobes again subdivided; first lat- 
eral lobe, about the size of the siphonal lobe, divided at its extremity 
into two tripartite lobes each of which is digitate; second lateral sinus 
shallow, divided into two rounded lobes each of which is slightly 
indented; second lateral lobe tripartite, central division not divided, 
other two bifid; third lateral sinus small bifid; remaining portion of 
septa not visible.” 
Suturally our type is very closely allied to S. ventricosus Meek, 
and it is quite probable if they do not belong to the same species 
that they are varieties of the same species. The specimen here 
described 1s much larger than Meek’s type of S. warrenz, but it has 
the same general form. It resembles the former species in aperture 
and suture, and the latter in body shape and coste. It is the belief » 
of the writer that S. warreni, S. wyomingensis and S. ventricosus are 
varieties of the same species. 
PRIONOTROPIS WOOLGARI-—MEEK. 
U. S. GEOL. SURVEY OF THE TERRITORIES, VOL. IX, P. 455. 1867. 
PED A hV Hips. 1 to 6, Mus, No.) P5931.) 
Further collecting and study of this form may reveal a new 
species. A comparison of the suture of P. woolgari with the suture 
of the form here figured and placed provisionally in the above species 
reveals many differences. However, these differences may be only 
such as exist between the young and the adult individuals of the same 
species. As the sutural differences seem to be the only well marked 
ones the original description will be given here and the reader asked 
to make the comparison of the figures, 
‘«Shell attaining a medium size, more or less compressed dis- 
coidal, the outer turn being proportionally more convex (including 
nodes) than those within; each volution embracing about one-fifth of 
the next within, and having its umbilical margin slightly indented by 
