164 CATALOG OF FOSSIL FISHES IN THE MUSEUM 



This genus is known by two species, G. politus Newberry, and G. 

 uddeni Lindahl, both from the American Devonic. The former ranges 

 through the Hamilton and into the Portage; the latter is known only 

 from the Hamilton. It is not clear to what group of fishes these spines 

 pertain. The suggestion has been made by Eastman''^ that they may 

 belong to Ptyctodonts, since they are frequently found in the same 

 beds with ptyctodont and rhynchodont dental plates; however, 

 beyond the fact of contemporaneity, there is no evidence for this view. 

 Newberry^' has remarked on the resemblance between these spines and 

 those known as Physonemus and Stethacanthus. 



Gamphacanthus uddeni (Lindahl) 

 (PI. 52, fig. i) 



This species is represented by three specimens, one of them (E 1875) 

 a nearly perfect spine (PI. 52, fig. i). This agrees closely with the 

 t)T)e figured by Lindahl, except that it seems somewhat more com- 

 pressed, a circumstance perhaps due to the mode of preservation. 



There has been some vagueness about the distinctions between 

 Gamphacanthus uddeni and the type species, G. politus. We have 

 therefore compared two of the specimens of the former (E 1875 and 

 E 1877) with the cotypes of G. politus Newb. (Amer. Mus. Coll.). 

 G. uddeni as compared with G. politus is (i) more compressed, as 

 shown by cross-sections of both the distal and proximal halves of the 

 spine; (2) has a larger number of stria tions, especially in the proximal 

 half; (3) the crenulations of the incised lines on the distal half are 

 much less conspicuous and in some specimens entirely absent. 



The three specimens in the Buffalo Museum are from the Hamilton 

 (Mid. Devonic) of Milwaukee, Wis. Collected and presented by Mr. 

 E. E. Teller, of Buffalo. 



E 1875 Nearly complete spine, in matrix, (PI. 52, fig. i). Length, 

 112 mm.; greatest width (at 2 cm. from proximal mar- 

 gin), 2>i- 



E 1876 Proximal half of spine, uncrushed and showing dimensions 

 of pulp cavity. 



E 1877 Proximal two-thirds of a spine somewhat larger than E 1875, 

 in matrix. No sinuosities whatever are to be seen along 



" Devonian Fishes of Iowa. Iowa Geol. Survey, xviii, 139, igo8. 

 '' Paleozoic Fishes of North America, 66, 1889. 



