TRIASSIC FISHES FROM SPITZBERGEN 
11 3 
the posterior limb. The tooth-bearing parts of the medial surface of the bone do not 
lie in the same plane as the toothless ones but are somewhat raised in relation to these. 
The bone-plates on the copula have strong, spheroid teeth and the tooth-plates of the 
branchial arches have smaller and blunt ones or partly spheroid ones. — The shape of 
the teeth on the whole closely resembles that of Colobodus. 
Sensory canals of the head. 
The sensory canals were strongly developed. The mandibular canal (me, PI. 19, 
fig. 1) on the supraangulo-angular has four or five large pores (p) as in Axelia and 
Mylacanthus. 
Axial- and fin skeleton. 
To judge from a small specimen (P. 23 g. PI. 17, fig. 3 ) the neural arches with their 
spinal processes are weak and fine, at least in the abdominal region. The same specimen 
also shows the first dorsal fin fairly well preserved and also remains of the supporting 
bone of the posterior dorsal fin. 
The most anterior dorsal fin (D u PI. 17, fig. 3 ) is exceedingly large and strong 
compared with what is usually the case in the Coelacanthids previously known. The 
number of lepidotrichia is about 15, all, except the most anterior one or possibly the 
two most anterior ones, long, broad and powerful. But they are not preserved in their 
original length. Their proximal part is unjointed for a long distance. The remaining 
distal part is closely jointed and the joints are short and broad. On the lateral surface 
the lepidotrichia had a characteristic sculpture in the form of pointed, fixed small 
tubercles or spines, which may sometimes be scattered irregularly, sometimes more or 
less distinctly arranged in two longitudinal rows. Especially towards the distal parts 
of the lepidotrichia this arrangement of the tubercles in two rows becomes more 
distinct. At the proximal end all the lepidotrichia are forked so as to articulate against 
the supporting plate (Sp.jjl The dorsal end of this plate (PI. 17, fig. 3 ) is broad and 
comparatively thick, the ventral end, on the other hand, is thinner, considerably narrower, 
and divided by a dorsally ascending sinus into two processes. 
The supporting plate for the posterior dorsal fin ( Sp 2 , PI. 17, fig. 3 ) resembles 
most closely in shape that of Undiha and Macropoma, i. e. its distal part is fairly small, 
while its proximal part consists of two long, narrow processes, the anterior one of 
which is directed fairly horizontally, the posterior one antero-ventrally. 
A number of detached lepidotrichia or, more correctly, fragments of these, show 
the same sort of sculpture on the lateral surfaces as is seen on the anterior dorsal fin. 
Others, on the other hand, have no such sculpture at all and, as far as one can 
understand, have belonged to some of the paired fins or the posterior dorsal fin. 
The claviculae had their ventral limb developed as a rather broad horizontally 
situated plate ( Icl , PI. ig, fig. 1) as in Wimania sinuosa. 
Squamation. 
The scales (PI. 19, fig. 2) have a very characteristic shape. For the most part 
their height and breadth is fairly similar, less often the breadth is greater. The greatest 
Stensio, Triassic Fishes from Spitzbergen, 15 
