1898-1902. No. 33.J UPPER DEVONIAN FISH REMAINS. 55 



As regards the two proved Holoptychius forms one belongs to a 

 new variety which is most nearly related to H. nobilissimus AG., which 

 appears to he extended in the Old Red both in the eastern and the 

 western portions of the northern hemisphere. It thus affords no definite 

 proofs. The other appears to be identical with H. tuberculatus NEWB., 

 which occurs in the Katskill, but may also be considered as H. gigan- 

 teus AG. which occurs both in N. America and in Europe. (Belgium, 

 Scotland, N. W. Russia and Baren Island.) 



Glyptolepis paucidens AG. and leptopterus AG. are highly charac- 

 teristic European forms which have only one relative in N. America, viz. 

 Gl. quebecensis WHIT, in the Upper Devonian of the Quebec Province 

 (Scaumenac Bay). 



Osteolepis is quite unknown in the American deposits, but on 

 account of the uncertain character of the remains cannot be given any 

 special significance. 



On the other hand, the tiny mussel belonging to the family Phtonia, 

 shows distinct connection with previously known American faunae, being 

 identical or very nearly related to Ph. cylindrica HALL from the Hamilton 

 Group in New York. 



The fishes thus appear to have different conditions to this form 

 emigranting from the marine invertebrat fauna. 



In the latter case the conditions are quite remarkable, particularly 

 in view of the marine fauna in the Silurian and Devonian series which 

 according to the investigations of 0. HOLTEDAHL and 0. E. MEYER show 

 a markedly American character. 



The Devonian fish fauna on Ellesmere Land thus appears at 

 least as regards the greater part, - - to have had a different origin to 

 that known in the case of S. E. Canada and the adjoining parts of the 

 United States. They must have had another connection with the faunal 

 province of N. Europe. 



The occurrence of the Psamniosteus forms gives an indication, for 

 they were formerly only known in N. W. Europe, as stated above. 



The earliest occurrence is in the Placoderm Sandstone of Poland, 

 belonging to the Older Middle Devonian. There are examples in N. 

 Scotland in somewhat later strata, and in N. W. Russia very commonly 

 in the Lower Upper Devonian, as also in Spitzbergen and Ellesmere 

 Land. According to our present knowledge it is natural to explain this 

 in the following manner. 



Psammosteus developed in the European province from the Lower 

 Devonian Drepanaspis Gemiindenensis. Whilst the latter was a marine 



