I 12 
ERIK A : SON STENSIO 
and in this respect rather resembled Axelia. The upper part of the anterior margin of 
the posterior limb is free for a considerable way, about as in Mylacanthus, or perhaps 
still more, and the anterior limb seems thus to have been comparatively low even at 
the most posterior part. 
Like the pterygoid the metapterygoid ( Mptg , PI. 18, fig. 2) is also very thick and 
strong. Only its anterior part, however, is preserved, so that no details can be obtained 
as to its shape. In relation to the pterygoid it has occupied the same independent 
position as in Spitzbergen species, i. e. it is connected with this bone only by its 
anterior border. 
The autangular ( Aang , PI. 19, fig. 1) is about the same as in Mylacanthus, but is 
more in situ. 
A part of the articular ( Art ?, PI. 19, fig. 1) is also possibly present. The curious 
shape of this bone in its present state of preservation does not, however, at first sight 
seems to support this view. In a Carboniferous Coelacanthus species in which I have 
observed the articular in a very good state of preservation its articulating fossa is, how¬ 
ever, divided into a lateral and a medial part by a ridge and both parts are relatively 
deep. As the supposed articular in S. asper is only accessible in cross-section its curious 
shape may easily be explained in connection with my observations on the above- 
mentioned Coelacanthus species. For it is conceivable that the part that is present forms 
a section just through the articulating fossa and that consequently what appear here 
to be process-like parts really constitute the lateral boundaries and parts of the medial 
ridge mentioned. 
The supraangulo-angular (Sang, ang , PI. ig, fig. x) was probably large but it is im¬ 
possible to establish whether it had a high and triangular shape similar to that of 
Axelia and Mylacanthus, or if it was long and low. Its sculpture consists of numerous 
long and fairly coarse striae, some also sharp. All these striae are situated close 
together and run horizontally in the longitudinal direction of the bone. As is the case 
in Axelia and Mylacanthus, they are limited to the part above the pores of the mandibular 
sensory canal and here it is more obvious than in these other genera that the part 
that has been situated ventrally of these pores has partly been directed downwards, i. e. 
has belonged to the ventral side of the mandible. 
A couple of fragments of some larger bone, possibly the opercular, are furnished 
with exceedingly powerful sculpture of the same type as on the supraangulo-angular 
(PL 20, fig. 1). 
The jugular plates (G, PI. 19, fig. 1) are narrowly oval, with the lateral and medial 
margins weakly convex. Their anterior ends are rounded off; their posterior ones are 
not preserved. The sculpture consists of longitudinal striae as on the supraangulo- 
angular, but seems to be somewhat weaker than on this bone. 
Dentition. 
The dentition is of the same typ'e as in Axelia and Mylacanthus. The teeth are 
generally, however, larger and stronger, while at the same time tooth-bearing bones 
are thicker and more powerful to a corresponding degree- On the pterygoid the teeth 
are obviously restricted in the main to the anterior limb and the antero-ventral part of 
