054 E. B. BRANSON 



spaced, linear markings, and has lateral margins, with denticles 

 obscure or lacking. The anterior face is marked by a high, thin, 

 almost knifelike ridge. 



This species is named for X. H. Brown, who collected the first 

 fishes from the Kmbar and who has rendered many valuable services 

 to geologists working in the Lander region. 



icanihus obscuracostotus n. sp. (PL IV, Fig. :, and Text-Figs a and 3) 

 This imperfect spine differs from that last described in that the 

 ribs are much finer and lower, in that they change gradually from 

 coarser behind to finer in front, and in that the spine narrows to a 

 knifelike edge in front. It agrees with the other spine in the 

 absence or obscurity of ornamentation. 



The length oi the part preserved is 105 mm., the width 27 mm. 

 at the outer end and 41 mm. at the inner. It was inclined backward 

 at a sharp angle. A large part of the inserted end is missing, but 

 in the part preserved the pulp cavity is open at the back for more 

 than cm. The cavity is shown at the outer and inner ends of the 

 spine in Figs. 2 and 3. 



Ctenacantkus omblyxipkias Cope (PI. II, Fig. 25, and Text-Fig. 5) 



1891. Ctenacantkus omblyxipkias Cope, Proc. U.S. Nat. Mus.. XIV, 440, 

 PL XXVII, Fig. 3. 



1903. Ctcnacantkus amblyxiphias Eastman, Bull. Mus. Comp. Zool., 

 XXXIX. PL :. Figs. 22 and 23. 



1903. Ctenacanthus atnblyxipkias Woodruff, Geo!. Surv. Xcbr., II, Tart II, 

 M PL XVIII. Fig. 5. 



ion. Ctcnacantkus omblyxipkias Hussakof, "Revision of the Amphibia and 

 Fishes of the Permian of Xorth America.'* Carnegie Institution Pub- 

 lication No. 140. pp. 161-62, PL ^o. Figs. and 6a. 



This fragment is referred provisionally to Cope's species though 

 it does not agree with his description in these respects: that the ribs 

 do not become smaller posteriorly so as to be of half the diameter 

 of the anterior ribs and that there are no tubercles on the posterior 

 margins. Most of the ornamentation has weathered off. but that 

 preserved agrees with Eastman's figures and not with Cope's. 



Eastman makes definite reference to the locality and formation 

 from which the specimens that he figures were collected, but Cope 

 and Hussakof give their specimens as from the Permian of Texas. 



