TRIASSIC FISHES FROM SPITZBERGEN 
25 * 
described a species from Canada in deposits that might also possibly be of Lower 
Triassic age. Finally a Platysomid form, described by Woodward 1910 (1910 b) from 
Madagascar, may be of Lower Triassic age as well (cf. Lemoine 1911, pp. 5—6). 
To these I have now to add at least two species of Platysomids found in the Lower 
Triassic of Spitzbergen. As far as can be judged from the fragmentary material present, 
they both resemble Platysomus , so that provisionally I have referred them to this genus. 
It is noteworthy in this connection that both one of the species from the Triassic 
of Spitzbergen, Platysomus nathorsti, and the Canadian species that Lambe took to be a 
Platysomus and called Platysomus canadensis, have attained an exceedingly large size. 
Genus Platysomus Agassiz. 
The genus Platysomus occurs both in the Carboniferous and the Permian. In Europe 
it appears in the latter formation together with Globulodus (Woodward 1891 b, p. 534) 
and Dorypterus (Zittel 1887 —1889, pp. 250—252; Reis 1891, pp. 167—170). From the 
possibly Lower Triassic strata in Madagascar Woodward (1910 b, pp. 2 —5) has described 
the new genus, Ecrinesomus, which, at least with regard to squamation, closely resembled 
Platysomus (cf. Andersson 1916 b, pp. 227—229). 
The supposed Triassic species Platysomus canadensis seems, according to the 
description given by Lambe (1914) to differ rather essentially from the usual type of the 
genus Platysomus. The most important differences are (1) the general shape of the body, 
(2) the position of the pectoral fins high up on the sides of the body, ( 3 ) the close 
agreement in the number of the lepidotrichia and the endoskeletal radials of the dorsal 
and anal fins, (4) the sculpture of the scale, which is said to consist of «pustules®. Lambe 
considers, it is true, that the characters enumerated here only have a specific value, but 
I do not feel convinced that this is the case, but think it more probable that we are 
concerned with a representative of a new genus. 
The two Platysomus species from the Triassic of Spitzbergen are still very 
incompletely known and, as already pointed out, I have only included them provisionally 
in the genus Platysomus. The smaller of them, which I shall describe below as Platysomus 
sp., seems to some extent to resemble Ecrinesomus. 
Platysomus nathorsti n. sp. 
(PI. 27, fig. 4; PI. 28, fig. 2; PI. 32, fig. I). 
This species is so far only represented with certainty by some fragments with 
scales, remains of fins and basidorsals (P. 141, P. 142). A number of detached scales of 
rather varying size also possibly belong to it (P. 2o3b, P. 692, P. 6 p 3 , P. 8yg). 
The species has attained a very considerable size. Certain of the larger scales are 
thus 85—90 mm high and 18—25 mm wide. By way of comparison we may mention that 
the larger scales in Platysomus canadensis, which is more than a metre in length, are 
only 65 mm high and 22 mm wide. 
The basidorsals, of which only the proximal ends are preserved, seem to have 
resembled most closely those in Birgeria. 
