TRIASSIC FISHES FROM SPITSBERGEN 
97 
Over the posterior part of the labyrinth region, behind the parieto-intertemporals 
and bounded laterally on each side by the dorsal edge of the supratemporo-extrascapular, 
there is a transverse row of six, scale-like, rounded, extrascapular plates («supratemporals») 
{Ext, text figs. 43, 44; Pis. 11—1 3 ; PI. 14, fig. 1) which did not lie in contact with the 
primordial neurocranium but formed a roof over the muscle fossae on the dorsal side 
of the labyrinth region, i. e. over the so-called temporal fossae. At the same time it is 
clear that they have not been closely united with the neighbouring bones, nor with 
each other either. 
The fronto-dermosphenotics (Fr. dspli, text figs. 3 g, 40, 43, 44; Pis. 11 — 1 3 ; PI. 14, 
figs, i-—4) are situated in the usual way over the anterior and middle parts of the 
orbitotemporal region. They slope, as usual, downwards and forwards and posteriorly 
they meet with the parieto-intertemporals in an obtuse angle. The suture between them 
and the latter bones falls at a vertical plane somewhat in front of the basisphenoid 
(text fig. 3 9) and is obviously straight. They are shorter in length than in W. sinuosa 
and only slightly longer than the parieto-intertemporals. In their posterior third they 
are a little broader than the latter,- otherwise, on the contrary, they are a little narrower. 
The medial and posterior margins are straight; the lateral margin has a posterior convex 
part corresponding to the broader third of the bone and an anterior slightly concave 
part, which in its turn shows two or three smaller concavities and convexities of the 
second rank; the appearance of the anterior margin is unknown at present. The centre 
of ossification is found in the same position as in W. sinuosa and from it there issues 
on the ventral side the large process, especially long- here (Alsph, text figs. 39, 40; 
Pis. 11—1 3 ; PI. 14, figs. 2, 3 ) which represents the alisphenoid. The process in question 
is, for the rest, broad and powerful. It is directed postero-ventrally and has been joined 
to the cartilaginous parts over the anterior lamella of the basisphenoid, as well as to 
the dorsal surface of the basipterygoid process. On its lateral side it is, as already 
pointed out above, crossed by a distinct furrow which must be considered to indicate 
with the greatest probability the course of r. ophthalmicus lateralis and possibly even 
r. opthalmicus trig-emini, if the latter has been united with it. 
Along the lateral margin of each fronto-dermosphenotic for about two thirds of its 
anterior part lie a row of four comparatively large, broad, four-sided supraorbitals (So, 
textfigs. 3 g, 40, 43, 44; PI. 14, figs. 1 — 4), which all have straight lateral and rather irregularly, 
curving medial margins, and are mutually united by somewhat undulating sutures. 
Anterior of the supraorbital row there follows a rather large bone ( Na . ant, text 
figs. 3 g, 40, 43, 44; Pis. 11— 13 ; PI. 14, figs. 1—4) which I have called the nasalo-antorbital. 
In lateral view (text figs. 3 g, 44) its shape seems to be almost that of an equilateral 
triangle with the apex lying rostrally and a little dorsally, the base lying caudally and 
a little ventrally. Its dorso-medial part rests upon the dorsal side of the ethmoidal 
region and thus covers the nasal capsule from above. All the other parts belong entirely 
to the lateral surface of the same region and surround the nasal aperture rostrally, 
ventrally and caudally, forming at the same time a septum that divides this aperture 
into an anterior (na 2 ) and posterior ( na s ) foramen, of which the first lies a little lower 
than the last. Both seem to have a rather rounded shape. The slightly concave posterior 
margin of the bone in question has probably formed part of the anterior boundary of 
Ste .11 si6, Triassic Fishes from Spitzbergon. 13 
