RaViMond : Fauna of Upper Devonian of Montana. 153 



narrow in fully grown shells. Adult shells are only slightly com- 

 pressed and young specimens are almost globular. None of the speci- 

 mens are entire, but from the shells at hand it is evident that the 

 living chamber occupies over half a volution. The surface markings, 

 which consist of very faint ridges, run slightly forward from the um- 

 bilicus and turn back on the venter, forming a shallow hyponomic sinus. 



Fig. 3. Outline drawing of two specimens of Prolobites simplex Raymond to show 

 sutures. Natural size. 



The cameras are deep in young specimens, a specimen 10 mm. in 

 diameter showing only three sutures in a full volution. The suture is 

 almost straight from the umbilicus to the ventral lobe, but shows a 

 shallow saddle near the umbilicus. This suture is much simpler than 

 that of the adult Prolobites delpJiinus (Sandberger), but is somewhat 

 like that of the variety atava described by Freeh. {^^Uber devoni- 

 sche Ammoneen,'''' p. 78, fig. 2)Z-) 



This genus has not been found elsewhere in the American Devonian. 



Locality. — This is the most common of the goniatites found in the 

 red shale of the Upper Devonian at Three Forks, Montana. 



Suborder EURYCAMPYLI Hyatt. 



Family MAGNOSELLARID.^ Beyrich. 



Genus Tornoceras Hyatt. 



Tornoceras crebriseptum sp. nov. 



(Plate VIII, figures 5-8.) 



In my preliminary paper referred to above, this shell was spoken of 

 as Cheiloceras sp. as the surface markings consist of nearly straight 

 lines with a very shallow hyponomic sinus. The course of the suture 

 is, however, so like that of Tornoceras that it must be referred to that 

 genus. In a recent paper (Die Cephalopodenfauna des hoheren Ober- 

 devon am Enkeberge. Neue Jahrbuch fiir Mineralogie, Geologic, 

 und Paleontologie, Beilage-Band XXVI, 1908, pp. 565-634), Wede- 

 kind has shown that the internal suture of the typical Cheiloceras is a 



