2 18 
ERIK A : SON STENSIO 
On each of the parietals there is a short transversally placed furrow (inp, PI. 27, 
fig. 3 ), which apparently represents a «pit-line» of sensory organs. It probably corres¬ 
ponds to the middle one of the three lines of this sort that are found on the posterior 
part of the cranial roof in Amia and other Teleostomes (cf. Allis 1889, pp. 502—509, 
Pl. XLII; igo 3 a, p. 187; 1905, pp. 406, 410, 418, 440, 452, 465, 469, 474, 484; Herrick 
1901, pp. 222— 223 ; PI. XIV, etc.). 
The skeleton of the unpaired fins. 
The dorsal fin (-D, PI. 27, fig. 3 ) is rather weakly developed. It is situated strikingly 
far forward and seems to have been opposite the ventral fins. Its shape cannot be esta¬ 
blished with certainty as the lepidotrichia are not preserved in their total length. The 
lepidotrichia, which are somewhat over 25 in number, are situated close together and 
are closely jointed. The fulcra are small and weak. 
The caudal fin is incompletely preserved and nothing can be established as to its 
shape. The ridge-scales on its dorsal lobe were probably rather small or at least not 
enlarged to any great extent. 
The skeleton of the shoulder girdle and the paired fins. 
Of the 'membrane bones of the shoulder girdle the little suprascapular and the 
supracleithral ( Scl, PI. 27, fig. 3 ) are partly preserved. Both these bones are pierced by 
the lateral canal and show the same conditions as to shape as are usual in the Palaeo- 
niscids. The sculpture consists of short and rather fine striae, parallel to the axis of 
length of the fish. 
The pectoral fins (Pc, PI. 28, fig. 1) are fragmentarily preserved. It can, however, 
clearly be seen that their lepidotrichia were unjoined in a long proximal part. 
The ventral fins (V, PI. 28, fig. 1) are small and short-based. The lepidotrichia, 
which seem to have been present to a number of 14 or 16, are closely jointed throughout 
their length. 
Squamation. 
Only on the most anterior part of the abdominal region immediately behind the 
supracleithral and the cleithral were there scales whose height was greater than their 
width (PI. 27, fig. 3 ; PI. 28, fig. 1). On the middle part of the sides of the abdominal 
region the scales are fairly rhombic or their width it somewhat greater than their height, 
farther posteriorly towards the caudal region their height decreases still more. This is 
also the case both towards the ventral side and the dorsum in the abdominal and the 
caudal regions. It is especially noteworthy that, as is shown in PI. 3 y, fig. 3 a large 
number of the scales situated towards the dorsum in each vertical row are even very 
low, which gives the whole squamation a very characteristic appearance. Some of the 
scales close to the base of the dorsal fin are even so low that their height is only 
l / s — r / 6 of their width. The dorsal ridge-scales, which are somewhat larger than the 
scales at their sides, do not seem to have been prominent. Some enlarged scales are 
found on the ventral side between the bases of the ventral fins (PI. 28, fig. 1). 
The majority of scales probably have the covered anterior area wide (PL 22, fig. 4). 
In addition they have a well developed articulatory spine and a serrated posterior margin. 
