TRIASSIC FISHES FROM SPITZBERGEN 
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The sculpture on the great majority of the high scales consists of numerous fine 
and rather short striae running rather obliquely in the directions backwards and 
downwards. The other scales have a coarser sculpture, which consists to a great extent 
of a relatively small number (the number decreases with the height of the scales) of 
wide, densely arranged striae (PI. 22, fig. 4), running somewhat parallel to the upper and 
lower margins. These striae are generally so long that they extent right across the 
exposed surface of the scales, each of them ending in one of the small spines on the 
posterior margin. Shorter striae, however, often occur inserted between these longer 
ones. Anastomisations between the striae are rare, and occur only on the scales of the 
most posterior part of the caudal region. 
Especially on the scales belonging to the ventral side and the anterior part of the 
sides of the abdominal region the striae are finely rugose, in about the same way as is 
figured by Traquair (1901, PI. i 3 , fig. 5) in Elonichthys pectinatus. 
A further characteristic of the sculpture on the great majority of scales is that 
the striae never bend off in a dorsal direction along in the anterior margin as in 
B. arcticus, and that between their anterior ends (PI. 22, fig. 4) there are practically 
always small tubercles or shorter striae. Finally it ought to be noted that the striae on 
the scales of the caudal region tend, according as one approaches the caudal fin, to 
take a direction parallel to the diagonal of each scale that can be drawn from the 
antero-dorsal to the postero-ventral corner. 
Remarks. — Boreosomus reuterskioldi is well separated from B. arcticus by its 
scale sculpture, but bears instead a striking resemblance to certain Acrolepis species, 
e. g. Acrolepis hopkinsi M’Coy (Traquair, 1909, p. 109—112; PI, 24, PL 25, fig. 6). 
It is named after Cand. Adam Reuterskiodl, my friend and my companion during 
the expedition to Spitzbergen in 1917. 
Geological occurrence and localities. — Boreosomus reuterskioldi is hitherto 
known only from the fish horizon at the following localities: Mt. Congress, Mt. Sture, 
Mt. Marmier, Mt. Trident and Mt. Andersson. 
Boreosomus sp. 
(Pi. 29, figs. i-3). 
Under the heading Boreosomus sp. I have grouped some mostly very fragmentary 
fish remains (P. 114, P. 120 — i3i) i all of which seem to have belonged to rather large 
individuals. The best preserved specimen (P. 120) is about 12 cm high just behind the 
head. The body has been fusiform, but no other details can be given as to its length 
or its general proportions. 
Visceral skeleton. 
Among the elements of the visceral skeleton there are only very badly preserved 
remains of the maxillary (#r, PI. 29, fig. 1), the mandible ( Md, PI. 29, fig. x), the 
preoperculum (Po, PI. 29, fig. 1) and possibly also of the operculum and the radii 
branchiostegi. The sculpture on these bones has consisted of fine tubercles, somewhat 
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