TRIASSIC FISHES FROM SPITZBERGEN 
87 
In the lower jaw are found remains of the supraangulo-angular {sang, ang, PL 10, 
fig. 3 ), coronoid (text fig. 38 B; Co, PI. 10, figs. 3 , 4) intercoronoideo-prearticular {Icor. 
pra, text fig. 37; PL 10, fig. 4) and one precoronoid plate ( Pco, PL 10, fig. 4). The 
intercoronoideo-prearticular extends in the usual way far forward on the medial side of 
the mandible and at least the most posterior precoronoid-plate is joined to its upper 
margin; this latter plate was comparatively long and low. 
The ossification in the ceratohyal (text fig. 38 Cj is considerably more powerful 
than in W. sinuosa, to judge from the parts of it that are present. In addition the part 
that is situated behind the large ventral projection is shorter than in the latter species. 
The epihyal (text fig. 38 D), on the other hand, is longer and narrower than in this. 
The opercular {Op, text fig'. 35; Pl. 10, fig. 1) is large and triangular in shape 
with one side at the front, one dorsally and one postero-ventrally. Of these the anterior 
and the dorsal ones, the latter of which is also the shortest of the three, are fairly 
straight, while the postero-ventral one, on the other hand, is convex. All the corners 
are well rounded, the antero-dorsal one, however, least. As on 
the cheek-plates the sculpture consists of small tubercles situated 
close together. 
The jugular plates {G, text fig. 37) are incompletely known, 
as they are only partly present as impressions. Their position 
in relation to the lower jaws, gill-arches and the urohyal is 
seen pretty well in text fig. 37, which is drawn directly from 
nature. 
The exact number of gill-arches is still unknown. On a 
section through specimen P. 226 (text fig. 37) only seven are 
found, but as this section was taken rather far forward and 
also obliquely it is quite possible that one or two have not been 
included. The ceratobranchials of course resemble the same bones in W. sinuosa and 
W. ? multistriata very considerably, but differ, however, distinctly from these by having 
a perichondral layer of bone that is as a rule considerably thinner, and a distinct endo¬ 
chondral ossification in the form of a spongy mass. Their position relative to the urohyal 
(Uhjr) is illustrated by text fig. 37, and in the same figure is also clearly seen the 
crista on the dorsal side of the latter bone, which both in this respect and in its 
development otherwise resembles most closely that of W. sinuosa. The suprascapulars 
are thin and weak. 
Dentition. 
The dentition has in the main the same character as in the Wimania species, i. e. 
the parasphenoid, pterygoid, coronoid, coronoideo-prearticular, and the membrane bones 
on the copula have small bluntly conical or somewhat rounded teeth placed close together; 
the labial margins of the jaws, on the contrary, are furnished with rather large and 
conical teeth; those of the gill-arches are small, fine and conically pointed, and are 
grown together into small plates at their bases. 
The postero-dorsal corner of the anterior pterygoid limb is without teeth over a 
rather considerable surface, and this toothless surface, though gradually becoming narrower, 
Text fig. 36. 
Sassenia tuberculata n. sp. 
Metapterygoid (Mptg) and ptery¬ 
goid (Pl) reconstructed from 
P. 225 and P. 226. Vs- (The 
unbroken line according to 
P. 226.) 
