TRIASSIC FISHES FROM SPITZBERGEN 
25 
and their sculpture, closely related to the type of teeth to which Agassiz and the majo¬ 
rity of the subsequent investigators have given the species name A. gaillardoti (Wood¬ 
ward, 1889 a, p. 279), but they differ very distinctly from this, especially in the uniformly 
narrow and low shape of the crown. 
The teeth of the middle and posterior transverse rows in Acrodus oppenheimeri 
also resemble to a certain extent the tooth to which Miss Wemple (1906) gave the name 
of A. oreodontus, but this has a little and prominent cone on the 
crown, which, to judge from her figure, has an additional special 
characteristic in the coarseness of its longitudinal crista. The 
relations between A. oppenheimeri and A. wempliae Jordan (Jordan, 
1907, p. 100) are still very uncertain. 
Acrodus oppenheimeri is named after Privatdozent Dr. J. Oppen- 
heimer of Briinn. I intended originally to name the teeth he 
had collected himself after him, but it turned out, as we have 
seen, that practically all of them were identical with Hulke’s species A. spitzbergensis. 
Geological occurrence and localities. — Acrodus oppenheimeri rarely occurs 
in the upper Saurian horizon. So far it has only been found at Mt Tschermak, Mt Saurie 
and south of Sassen Bay on the mountain between De Geer Valley and Flower Valley. 
Cephalic spines, fin-spines and dermal denticles belonging to Hybodus, 
Acrodus or closely related genera. 
Cephalic spines. 
Of cephalic spines only a basal plate (P. 351) has been found so far. Its appearance 
and size are shown in PI. 1, fig. 11. 
Text fig. 9. 
Acrodus oppenheimeri n. sp. 
Dermal denticles. A. From 
the lateral surface. B. From 
the dorsal or ventral edge. 
Magnification i5/i. 
Geological occurrence and locality. — Bone-bed 33 m above the fish 
horizon, Mt Viking. 
Fin-spines. 
At present only four fin-spines are known of the type characteristic of Hybodus 
and Acrodus (P. 42, P. 102, P. 282 , P. 883 ). 
The best preserved of these is P. 282, of which only a small part is missing at 
each. end. In its present state of preservation it is 91 mm long, but originally it was 
probably about 100 mm. The maximum width between the anterior and posterior edges 
is 10 mm. PI. 1, fig. 17 clearly shows its shape and sculpture and makes a special de¬ 
scription superfluous. It ought, however, to be pointed out that the ridges are better 
separated than the figure suggests; this is due to the fact that the interspaces could 
not be quite freed from stone in the preparation. For the same reason the ridges also 
seem here and there to be a little varicose, which as a matter of fact is not the case. 
They all grow gradually and uniformly narrow towards their distal ends. 
The fin-spine P. 42 (PI. 1, fig. 18) is represented in its present state of preservation 
by a portion of the distal part. At the proximal end this portion measures about 3 o mm 
Stensio, Triassic Fishes from Spitzbergen. 4 
