TRIASSIC FISHES FROM SPITZBERGEN 
log 
1907 (1907a, p. i 36 , Pl. VIII, figs. 2, 8) with the letter m in Macropoma and Mawsonia 
and 1909 with the letter a in Macropoma (p. 176; Pl. XXXV, fig. 9, Pl. XXXVII, fig. 5). 
The supraangulo-angular (Sang, ang , PL 18, fig. 4) is, as in A. robnsta, triangular in 
shape and its height is. fairly great. The base is straight, the antero-dorsal margin 
perhaps concave and the postero-dorsal one convex. Unlike that of A. robnsta, however, 
the latter has a broad and rather large process. Both the dental ( De, Pl. 18, fig. 4) and 
splenial ( Spl , Pl. 18, fig. 4) are poorly preserved. 
The sculpture of the mandibula is restricted to the supraangulo-angular and on 
this, as in A. robusta, to the part dorsally of the pores of the mandibular sensory 
canal. It consists of strong and somewhat elongated tubercles, which are situated 
fairly close to one another and are as a rule arranged parallel to the longitudinal axis 
of the mandibula. 
As in other Spitzbergen Coelacanthids the opercular is of considerable size. It is 
only preserved, however, in its ventral half but even this fully shows that it had a 
very characteristic shape, distinctly different from that of all other known species (Op, 
Pl. 18, fig. 4). At least the ventral half of the anterior margin is weakly convex or 
almost straight. The postero-ventral margin has a broad, fairly deep acute-angled sinus 
in its ventral part; on account of it the ventral part of the bone appears as a broad 
and rounded but fairly well defined process. Dorsally of this larger sinus there follow 
on the postero-ventral margin a number of smaller sinus, which decrease, however, 
rather rapidly in depth and size upwards. By means of these sinus the postero-ventral 
margin is divided into lobes, which in their turn are split up by other smaller sinus 
into lobes of the second order. Along the anterior margin of the bone there extends 
a rather broad zone without sculpture. The other part of the lateral surface has a 
sculpture which, as on the supraangulo-angular, consists of somewhat elongated strong 
tubercles with a horizontal arrangement. 
Nothing is preserved of the branchial arches. On the other hand remains of strong 
and thick plates, which have probably covered the copula, are found. A part, possibly 
of a jugular plate (G? Pl. 18, fig. 4), has the tubercular sculpture characteristic of the 
species, but. the tubercles are arranged so that they show a certain radiation from a point, 
which was probably the centre of ossification. 
Dentition. 
The dentition is adapted for crushing and agrees very closely on the whole with 
that of A. robusta. (Pl. 18, fig. 4 shows a number of scattered remains of the supracopular 
plates and smaller plates from the branchial arches.) 
Sensory canals of the head. 
The sensory canals have apparently been strongly developed, but only the mandibular 
canal (Pl. 18, fig. 4), is partly preserved. This has pierced the supraangulo-angular and 
the splenial in the usual way and, as in A. robusta , it was developed with large oval pores 
(p, Pl. 18, fig. 4), four or five of which were situated on the supraangulo-angular and 
at least two on the splenial. 
