644 E- B. BRANSON 



teeth are smooth, but in older forms incipient, transverse wrinkling 

 appears, and is more prominent on the wings. The ends of the 

 central ridge project beyond the base. The base is a rhomboid 

 with obtuse angles of slightly more than ioo degrees. The wings 

 project downward and give to the bottom of the teeth a trough- 

 like appearance, with the trough slightly deeper in the middle. 

 In the largest specimen the greatest thickness is about 15 mm., 

 the greatest length 34 mm.. and the greatest width :8 mm. The 

 average size is considerably smaller. The crown surface is closely 

 and evenly punctate with subcircular punctations. 



Co- types of it are 31 specimens from the Popo Agie and Bull 

 Lake regions. It is No. 703 of the paleontological collection of the 

 University of Missouri. About 25 other fragments of teeth are 

 in the collection. Owing to the thickness of the teeth they are 

 usually well preserved. 



The foregoing description was written before the writer had 

 seen Professor Stuckenberg's paper, '"Die Fauna der obercarboni- 

 schen Suites des Wolgadurchbruches bei Samara," 1 in which he 

 figures the same species but lists it as "genus et sp. indeter.," 

 and does not describe it. Stuckenberg's figures are reproduced in 

 PI. I, Figs. 22-24. 



ipodus corrugatus Newberry and Wort hen (PI. Ill, Figs. 1-6) 

 1S70. Orodus corrugatus X. and W., Pal. III., IV, 358, PI. Ill, Figs. 18 and iSa. 

 1875. Agassisodus corrugatus St. J. and W., ibid., VI, 323-24, Fl. VIII, Fig. 24. 

 1S70. Cliiastodus obvallatus Trautschold, Now. Mem. Soc. Imp. Xatur. 



Moscou., XIV, 156-57, PI. XVIII, Figs, ioa-d. 

 1SS0. Cam pod us corrugatus Woodward, Cat. 0/ Fossil Fishes. Part I, p. 239. 

 igo2. Campodus corrugatus Eastman. American Naturalist, XXXVI, S53-54, 



Fig. 2. 



Trautschold's figures of Ckiastodus obvallatus from the Mos- 

 cowian of Russia are reproduced in Plate III for comparison with a 

 specimen from above coal No. 5 at Galatea, Illinois, and the 

 differences seem too small to recognize as specific. The Russian 

 specimen has deeper lateral lobations than the one figured, but a 

 specimen in the Walker Museum of the University of Chicago 

 has lobations of about equal depth. The surface ridges appear more 



1 Mcnwires du Cotniti Giologique, Nouvelle Serie, Livraison 23, 1905. 



