TRIASSIC FISHES FROM SPITZBERGEN 
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strikingly narrow at one place between the orbitae. A special characteristic of it is the 
absence of processus ascendentes and the fact that its extension backwards is exceedingly 
slight, as its posterior end is situated beneath the most anterior part of the labyrinth 
region. Sometimes it has on its anterior half upward-bending lateral parts, which have 
covered the lateral surfaces of the interorbital wall ventrally. Sometimes, on the other 
hand, as in e. g. Axelia and probably also other of the forms related to this, the posterior 
part of the bone in question is in stead powerful and thick under the basisphenoid and has 
there on each side a similarly thick dorsally directed lamella, which is connected with the 
ventral processes from the basisphenoid corpus. These lamellae and the dorsal portion of the 
part of the parasphenoid situated between them may perhaps, to judge from their 
structure, be developed in cartilage. 
Nothing certain is yet known about the vomeres. 
A characteristic feature of the dermal cranial roof in Coelacanthids is the fact 
that fusions have taken place between the homologues of certain bone elements 
that are independent in more primitive Crossopterygian forms {Rhipidistia; Watson 
Day, 1916; Goodrich, 1919; Allis, 1919b). Thus the following bones of the Rhipidistia 
may in Coelacanthids be fused: the supratemporal with a part of the lateral extrascapular 
plate (tabular), the parietal with the intertemporal, the frontal with the alisphenoid and the 
dermosphenotic, and the nasal elements with the antorbital. According to the elements 
fused I have called the compound bones formed in this way in the Coelacanthids by the 
double names of supratemporo-extrascapular, parieto-intertemporal, fronto-dermosphenotic 
and nasalo-antorbital. 
On each side of the median line the supratemporo-extrascapular forms the postero¬ 
lateral, usually strongly projecting corner of the dermal cranial roof. By a generally 
well developed forward and downward pointing process it is connected with the posterior 
upper part of the corpus of the prootico-opisthotic of its side. Its posterior part forms the 
lateral boundary of the paired muscle fossa («fossa temporalis*) on the posterior part 
of the roof of the labyrinth region. 
The parieto-intertemporals are generally large, somewhat rectangular bones, meeting 
in a median suture. They always occupy an almost horizontal position, while the bones 
in front of them all belong to the part of the cranial roof that slopes forward. The 
angle of the cranial roof is thus always between them and the fronto-dermosphenotic 
bones. In a number of forms they are somewhat narrower at their anterior end than at 
the posterior (Wimania , Axelia), in others, on the contrary, they seem to be of nearly 
equal width throughout their length. From their ventral surface they send out in the 
neighbourhood of the lateral margin a ventrally pointing rather low lamella, which 
covers a dorsal part of the lateral wall of the labyrinth region from the outside. 
Behind the parieto-intertemporals and bounded at the sides by the supratemporo- 
extrascapulars a transversal row of extrascapular plates has been situated. These plates 
are only preserved, however, in Axelia, where they are six in number and have a rounded 
scale-like shape. They have been loosely situated in the corium above the muscles that 
had their insertion into the so called «fossae temporales*. 
The anterior ends of the fronto-dermosphenotics seem as a rule to reach to the 
ethmoidal region, while the posterior ends are situated above or just in front of the 
