TRIASSIC FISHES FROM SPITZBERGEN 
215 
Squamation. 
The shape and sculpture of the scales were described earlier by Woodward (1912). 
In order to be able to show more precisely the difference between this and the species 
described below it is, however, necessary to state some additional details as to the 
sculpture. I have all the more reason to do so as one of the specimens found after 
1912 has its scales partly in a fine state of preservation (P. 695, PI. 27, fig. 2). 
One always finds immediately behind the covered anterior area on each scale one 
or a couple, sometimes even three or more, ganoine ridges mainly running parallel to 
the anterior margin of the scales. Sometimes one or more of these ridges may be divided 
into shorter, mutually'independent pieces. The most anterior ridge, or sometimes the 
two most anterior ones, usually have their lower ends finishing directly at the ventral 
margin of the scales. It may also happen, however, that they are both bent backwards 
in their ventral parts, so that they run for a bit along the ventral margin, but this is 
more often the case with the second one counting from in front. When a third one, or 
possibly still another is present, these two are always bent and pass over into the broad 
and flat ridges, running obliquely backward and downward, that occur on the remaining 
and far greater part of the exposed surface on each scale. The ridges of this latter 
category often anastomose at their posterior parts and sometimes also along the ventral 
margin of the scales in the way shown in PI. 27, fig. 2. 
All the ridges, both those running parallel to the anterior margin of the scales and 
the others, are smooth and level. The fine corrugation or a similar appearance that 
often occurs in the species described below is entirely lacking here. Finally it is worth 
mentioning that the ridges are as a rule very flat and considerably wider than the furrows 
between them. 
Remarks. —- Boreosomus arcticus is well characterized as an independent species 
by its scale sculpture. Especially characteristic are the frequent anastomosings of the 
ridges towards the posterior and lower margins of the scales. Another important 
character consist in the direction of the ridges that follow along the anterior margin 
of the exposed surface of the scales. 
Geological occurrence and localities. — B. arcticus is known from Salomon’s 
bone-bed at Mt. Congress, from the fish horizon at the south shore of Sassen Bay at 
Mt Marmier, and from the Triassic strata at Horn Sound. 
Boreosomus reuterskioldi n. sp. 
(PL 22, fig. 4; PI, 27, fig. 3; PI. 28, fig. 1). 
To this species I assign remains of five specimens (P . 115— P. 117; P. 119; P. 678). 
It is possible that a number of head bones (P. 676), not determinable in detail, and a 
number of detached scales (P. 118; P. 777; P. 798) also belong here. 
The material present is not adapted to give any exact idea of the general shape 
and proportions of the species. One can, however, conclude that the shape of the body 
was fusiform and that the total length of the best preserved specimens (P. 117 and 
P. 119) amounted to 20—25 cm. If> however, one of the two doubtful specimens (P. 676) 
