TRIASSIC FISHES FROM SPITZBERGEN 
21 
numerous small branches, directed obliquely and basally, throughout their length, while 
such branches are sparse on the above mentioned teeth of A. spitzbergensis and are 
always restricted to the basal ends of the striae. The conditions of the sculpture on 
the medial side are unknown and similarly nothing can be said as to the primary 
longitudinal crista or possible secondary longitudinal cristae. Both the root and the 
crown have been rather wide. 
With regard to the microscopical structure the conditions of the teeth of this 
species seem to have been normal (cf. Jaekel, 1889). 
Remarks. — The teeth described here are all of about the same size and have 
various features in common with regard to their sculpture, so I considered it proper, 
at least provisionally, to group them in one species. On account of their relatively 
strong sculpture I have suggested the species name scaber for them. 
Acrodus scaber seems, as far as is known, to be a well defined species, resembling 
A. spitzbergensis most closely. 
Geological occurrence and locality. — The material of A. scaber was, as 
already mentioned, collected by Prof. Dr. W. Salomon in the bone-bed found by him 
at Mt Congress. It thus comes from the lowest Triassic. 
Acrodus oppenheimeri n. sp. 
(PI. 3 . figs. 1 —11.) 
The material of this species that is present consists altogether of almost 40 teeth, 
most of which, however, are very fragmentarily preserved. Except for a tooth that was 
among the material from Nordenskiold’s Spitzbergen expedition (1864) kept at the State 
Museum, Stockholm, all the teeth (P. io 3 — 105) belong to the Palaeontological Museum 
of IJpsala. 
Somewhat over 3 o teeth occur together on a slab of slate (P. 105) in such a way 
that they undoubtedly belong to one and the same individual. It is impossible to de¬ 
cide whether they come from the palatoquadrate or the mandibula or from both. 
Together with them are found badly preserved remains of calcified cartilage and a 
number of dermal denticles. When nothing is said to the contrary the following de¬ 
scription is based on specimen P. 105. 
Teeth. 
The teeth of the most anterior transverse rows are characterized, as in A. spitz¬ 
bergensis, by the presence of a principal cone and distinct lateral cones on their crowns. 
In the present material there are only two such teeth. 
One of* them, the one figured on PI. 3 , fig. 1, is only preserved as an impression 
of one side and even this impression is in its turn greatly destroyed. The crown has 
probably had a total length of about 1 x mm. It is weakly bent so that its distal con¬ 
tour is convex from one end to the other. Its powerful, comparatively high and sharply 
pointed principal cone is a very characteristic feature. On one side of the principal 
