192 
ERIK A : SON STENSIO 
The caudal fin is large and strongly heterocercal (PI. 24, fig. 1), deeply cleft and 
nearly equilobate. The lepidotrichia are very numerous, situated close to each other and 
are ramified dichotomically in their distal parts. Apart from a shorter proximal part 
they are densely jointed throughout. The joints are always longer than broad and are 
often somewhat sinuated into the shape of an hour-glass at the middle. The dorsal lobe 
has a row of strong ridge-scales on its dorsal edge. All the lepidotrichia of the fin lack 
ganoine covering. 
The haemal spines (Jisp, PI. 24, fig. 1) were long and strong in the most anterior 
part of the ventral lobe, but slightly flattened from the sides. Towards the middle and 
posterior part of the same lobe they decrease in size but seem to maintain the same 
shape as in the anterior part. 
The skeleton of the girdles and the paired fins. 
The pectoral fins in B. mongeoti are still unknown, as is also the case with the 
shoulder girdle. 
The pelvic girdle and the ventral fins. Two ventral fins, found together in a 
nodule (P. 154) seem to have certainly belonged to the species in question. As these 
fins do not occur together with other parts of the skeleton it is impossible to decide 
their original position in relation to other fins. Nor is it possible to say which of them 
was originally the right and which the left one, and of course under such circumstances 
one cannot decide either which of their surfaces was situated dorsally and which 1 
ventrally. This state of affairs is, however, of no importance at all for the description 
and interpretation of the different skeletal elements. 
The two fins are fairly well preserved, but one of them — the left one as they 
now lie — has both its lepidotrichia and inner skeletal elements turned 180 0 from its 
original position, in the way seen from text fig. 68 A and PI. 23 , fig. 3 . They seem to 
have had a rather long base, a character that is also found in many other Palaeoniscids, 
e. g. Clieirolepis (Woodward, 1891b, p.451; 1898 a, p. 85, fig. 62; Regan, 1904, p.334), 
Nematop thy chius (Traquair, igog, p. 118—119, PI. XNVI, fig. 1) Cryphiolepis (Traquair, 
1907, p. 105, fig. 4, Elpisopliolis (Woodward, 1908 a, pp. 17, 20, PI. IV, fig. 2), Atherstonia 
(Woodward, 1891 b, p. 514), Coccolepis (Traquair, 1911 b, p. i 3 , fig. 2, PI. I, fig. 1); Woodward, 
1895 a, p. 7; PI. I, fig. 16; 1898a, p. 86; 1915, p. 33 ) etc. The lepidotrichia are very numerous. 
No less than about 50 are preserved, but it is probable that the total number has been 
somewhat larger. They are all incomplete at the distal ends and nothing certain can there¬ 
fore be discovered as to the shape of the fins. They are also strikingly fine, are situated 
close together and are without ganoine covering. Apart from a proximal part they are 
fairly closely jointed and towards the distal ends they are also possibly dichotomically 
ramified. The joints are, it is true, not specially long, but their length is still considerably 
greater than the breadth. 
The endoskeleton in each fin is represented in its present state of preservation by 
a large bone-plate (Pv) and ossified remains of radials (po , do, text fig. 68 A; PI. 23 , fig. 3 ). 
The bone-plate Pv is represented in the present state of preservation only by an 
incompletely preserved impression. To judge from this it had a wide posterior and a 
narrow anterior part, which passed fairly rapidly into each other. It is impossible. 
