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ERIK A : SON STENSIO 
preserved. Its numerous lepidotrichia are situated close together and are closely jointed 
practically right down to the base. Their distal parts are dichotomically ramified. The 
dorsal lobe has strong and large ridge scales; the ventral lobe has very small fulcra. 
Beneath the ridge-scales of the dorsal lobe there follows a series of endoskeletal 
radials ( Icr, PI. 25, fig. 3 ) in the usual way (cf. Schmalhaussen, igi 3 a, pp. 20—35). The 
haemal spines (lisp, PL 25, fig. 3 ) that belong to the anterior part of the fin and form a 
support for the lepidotrichia of the ventral lobe, are long and strong but not flatened. 
The other haemal spines following behind those mentioned are weaker and of course de¬ 
crease in size posteriorly to the same extent as the dorsal lobe grows narrower. — All 
the lepidotrichia in the unpaired fins probably lacked a covering of ganoine. 
The skeleton of the girdles and the paired fins. 
Nothing is preserved of the primordial shoulder girdle or its ossifications. Its mem¬ 
brane bones show the same conditions as in Palaeoniscids in general (text fig. 69; PI. 26, 
figs. 1, 2; PI. 27, fig. 1). We can distinguish the suprascapular (Sscap), supracleithral (Scl), 
cleithral (Cl), and clavicle (Icl). 
The sculpture on all these bones consists as a rule of short, dense striae or some¬ 
what lengthened tubercles. The suprascapular and a dorsal and larger (p art of the 
supracleithral has its striation mainly oriented so that it is parallel with the longitudinal 
axis of the fish. Towards the ventral end of the supracleithral the striation becomes 
oblique, the striae taking a somewhat ventral direction. On the cleithral and clavicle the 
the striae run principally in a dorsi-ventral direction, though here and there deviations 
and irregularities occur in their arrangement. 
The pectoral fins (Pc, PL 25, fig. 3 ; Pl. 26, fig. 1; Pl. 27, fig. 1) are well developed 
and triangular in shape. The lepidotrichia are numerous — about 3 o — and generally un¬ 
jointed in the proximal two-thirds of their length. Only some of the most posterior and 
smaller ones might possibly have been jointed to any greater extent. All the lepido¬ 
trichia are dichotomically ramified at their distal ends and seem to lack ganoine covering. 
Fulcra are present, though not particularly large. Of the endoskeleton of the pectoral 
fin only few radials (R, Pl. 26, fig. 1) are preserved. 
The ventral fins (V, Pl. 25, fig. 3 ; Pl. 26, fig 1) are very incompletely preserved. With 
regard to their position relative to the other fins no certain statement can be given. 
Their lepidotrichia were presumably densely jointed troughout their length, and in 
addition were probably without any ganoine covering. 
Squ amation. 
The scales are on the whole very small and thin. Only immediately behind the 
cleithral do we find a couple of vertical rows with obviously enlarged scales (Pl. 26, 
fig. 1; Pl. 27, fig. 1). 
In shape the scales in the rows immediately behind the shoulder girdle are somewhat 
higher than wide. Otherwise the scales of the abdominal region seem to have been 
fairly rhombical, apart from those of the ventral side, which were probably somewhat 
wider than high. Nothing is known in detail as to the shape of the scales in the caudal 
region. 
