ERIK A : SON STENSIO 
Order ActinopterygiL 
Family Palaeoniscidae. 
Historical remarks. 
In 1873 Martin (723—734) had grouped the genera Palaeoniscus Blainville, Acrolepis, 
Agassiz, Amblypterus Agassiz, Pygopterus Agassiz, Saurichthys Agassiz and Cheirolepts 
Agassiz in one family to which he gave the name of Palaeoniscidae. But the family 
obtained its present defination by Traquair’s works and it is Traquair’s great merit 
that he has elucidated in detail its systematic position in connection with a thorough 
study of the osteology of the forms belonging to it. Traquair’s numerous works on this 
subject (cf. Dean, 1917, Bibliography of fishes, pp. 551 — 557) and especially his large 
monograph on the Palaeoniscids of the British Carboniferous formations (1877—1914) 
constitute a great advance in our knowledge of the anatomy of the more primitive 
Actinopterygii in general. 
In the work just mentioned Traquair dealt also with the earlier history of the 
Palaeoniscids, and so I merely refer to his account (1877 a, pp. 1 — 13 , 34—42) for 
information about this. 
In addition to Traquair it is especially Woodward (1889 b, c, d; 1890 a; 1891 b; 
i 8 g 3 a; 1895 a; 1898 a; igo 3 ; 1906 a, b; 1908 a; 1910 a; 1912 etc., cf. Dean 1917, 
Bibliography of fishes, pp. 645 — 653), who has devoted his attention to the study of the 
Palaeoniscids during the last few decades. Among other investigators who have also 
been occupied with them recently may be mentioned Abel (1919, pp. i 83 —190), Bridge 
(1878, pp. 719—724), Broom (1909 a; igi 3 a, b), Dames (1888), Eastman (1907, pp. 256— 
274), Fritsch (1895, vol. 3 , pp. 76—80, 83 —126), Goodrich (1909, pp. 210— 223 ; 3o2— 
32 i), Lambe (1910; 1916), Modie (1915) and Tornquist (1904). 
The majority of the investigators who have worked at the Palaeoniscids have in the 
main treated their material from the point of view of its classification and stratigraphical 
distribution. Besides Traquair, Woodward and Bridge it is thus really only Abel, Broom, 
Fritsch and Modie who have made contributions of any great importance to our know¬ 
ledge of the anatomy. It is true that in many cases the state of preservation of the 
material present has not been suitable for a more detailed investigation, but sometimes 
at least better results could surely have been attained; this is my experience from the 
study of the Palaeoniscids from the Triassic of Spitzbergen. 
Some remarks on the geological appearance and the geogra¬ 
phical distribution of the Palaeoniscids, with special reference to 
the Triassic forms. 
The Palaeoniscids appeared, as has already been mentioned, already in the middle 
Devonian with Cheirolepis (Woodward, 1891 b, pp. 451—457) and Rhadinichthys (Traquair, 
1910, pp. 126—127; Eastman, 1907, pp. 258—260, 282; Stensio, 1918 a, p. 71) and perhaps 
