﻿PTTCTODONTID^!. 39 



The following species are recognized : — 



Ptyctodus calceolus, J. S. Newberry, Eep. Geol. Surv. Ohio, vol. ii. 

 pt. ii. (1875), p. 59, pi. lix. fig. 13 : Rinodus calceolus, 

 Newberry & Worthen, Pal. Illinois, vol. ii. (1866), p. 106, 

 pi. x. fig. 10. — Hamilton Group (Upper Devonian); Illinois 

 and Iowa. [Abraded tooth, the type species of Rinodus.~] 



Ptyctodus obliquus, C. H. Pander, Ctenodipt. devon. Syst. (1858), 

 p. 64, pi. viii. figs. 1-9, 11, 13-22 : Ptyctodus ancinnatus, 

 C. H. Pander, ibid. p. 64, pi. viii. figs. 10, 12 : Aulacosteus 

 cochleariformis and A. oviformis, E. von Eichwald, Leth. 

 Rossica, vol. i. (1860), pp. 1548, 1550, pi. lvii. fig. 8.— 

 Middle Devonian ; Governments of St. Petersburg, Nov- 

 gorod, and the Baltic Provinces. [Abraded teeth ; School 

 of Mines, St. Petersburg. The type species.] 



Genus RHYNCHODUS, Newberry. 

 [Rep. Geol. Surv. Ohio, vol. i. pt. ii. 1873, p. 307.] 

 In the type species of this genus, four teeth have been found 

 associated in a group, suggesting that those of the upper and lower 

 jaws were similar, a single pair occurring in each. 



The following species are known : — 



Rhynchodus eoccavatus, J. S. Newberry, Rep. Geol. Surv.Wisconsin, 



vol. ii. (1877), p. 397, and Palaeoz. .Fishes N. America 



(Mon. U.S. Geol. Surv. no. xvi. 1889), p. 50, pi. xxix. 



fig. 1. — Hamilton Group (Upper Devonian) ; Milwaukee, 



Wisconsin. 

 Rhynchodus occidentalis, J. S. Newberry, Ann. New York Acad. 



Sci. vol. i. (1878), p. 192. — Hamilton Group; Iowa. 



[Columbia College, New York.] 

 s, Bhynchodus secans, J. S. Newberry, Rep. Geol. Surv. Ohio, vol. i. 



pt. ii. (1873), p. 310, pi. xxviii. fig. 1, pi. xxix. figs. 1, 2, 



and Palseoz. Pishes N. America (1889), p. 47, gl. xxviii. 



figs. 1-3. — Corniferous Limestone (Middle Devonian) ; 



Ohio. [The type species, Columbia College.] 

 Bhynchodus, sp. ind. : Physichthys hoeninghausii, H. von Meyer, 



Palseontogr. vol. iv. (1855), pi. xv. fig. 9 (errore). — 



Devonian ; Eifel, Germany. [Museum of Comparative 



Zoology, Cambridge, Mass.] 



Genus PAKffiOMYLUS, nov. 

 In the type species of this genus (P. frangens) the symphysis is 

 as broad as in Edaphodon. 



