TRIASSIC FISHES FROM SPITZBERGEN 
73 
are on the contrary not to be observed. Besides, even if a dermopalatine occurs in certain 
Coelacanthids, this fact has not yet enabled us to prove that the presumed maxillary in 
Macropoma and Wimania is really identical with the dermopalatine. 
With regard to the mandibula of the Coelacanthids it has been necessary, as in 
the case of the bones of the cranial roof and the cheek, to introduce other terms than 
those previously used. In doing this I have followed chiefly the results gained from 
Branson’s (1905, pp. 601— 6 o 3 ), Broom’s (igi 3 d, pp. 73—78; igi 3 e, pp. 563—595), 
Gregory’s (1915, pp. 325— 334), Watson’s (1912 a, pp. 10 — 12; 1912 b, pp. 573—587), 
Wills (1916) and Woodward’s (1898 a, pp. 123—140; 1907 b, pp. 298— 3 oo) works on 
the homologues of the bones of the mandibula in primitive fishes and Tetrapods, but 
at the same time I have also gone farther in the direction opened up by these investigators, 
for reasons that will be given below. I now give the infradental of the Coelacanthids 
as the splenial, the large post-splenial plate as the intercoronoideo-prearticular, and the 
anterior splenial plates as the precorofioids; further I consider it probable that the bone 
formerly described as the angular (sometimes as the articulo-angular) may be composed 
at least of the supra-angular, the angular, and possibly also the pre-angular, so that it 
ought to be called the supraangulo-angular.*) The coronoid is situated quite on the 
medial side of the mandibula and ought thus to be only partly homologous with the 
bone termed in the same way in Tetrapods. For the present, however, 1 thought 
I ought to retain this name, especially as, according to Watson’s (1912 a, pp. 11—12) 
statement, the coronoid in certain primitive Stegocephalians ( Loxomma ) was developed 
in a similar way. 
In W. sinuosa the mandibula is very incompletely preserved and it is therefore not 
possible to ascertain its shape with certainty to any great extent. The reconstruction of 
it in text figs. 25 and 26 B is consequently given with the reservation that many details 
may really be different. It seems possible, however, to make one certain statement, 
namely that the mandibula as a whole has been rather large and powerful. Of its bones 
the dental ( De , text fig. 25; PI. 5, fig. 2; PI. 6, figs. 1, 4), the supraangulo-angular (Sang, 
ang, text fig. 25), the intercoronoideo-prearticular (Icor. pra, PI. 4, fig. 2; PI. 6, figs. 1, 2, 3 ; 
PI. 7, fig. 3 ) and possibly the autangular (A. ang, PI. 4, fig. 2; PI. 7, fig. 4) as well are 
represented only by fragments. The coronoid (Co, text figs; 25, 26 B; PI. 6, figs. 1, 2, 3 , 4; 
PI. 7, fig. 5), on the other hand, is completely preserved and lies fairly well in situ in 
relation to the intercoronoideo-prearticular, with which it has been closely connected. Its 
shape is triangular with a somewhat rounded upper and anterior corner. Two precoronoids 
(Pco, PI. 5, fig. 2; PI. 6, figs. 1, 4) are also fairly well preserved. 
The large mandibula presupposes a powerful adductor muscle. This has certainly 
had its origin partly on the palatoquadrate, but it is probable that it has also arisen on 
the neurocranium, in the shallow fossa on the lateral wall of the labyrinth region, which 
has been described above. If this is correct, the arrangement of the musculature would 
thus in this respect have resembled that of the recent Dipnoi (Luther, 1913, pp. 33—45; 
Adams, 1919, pp. 80— 83 ), although specialization has gone considerably farther in the 
latter than in the Coelacanthids (cf. Reis, 1892, pp. 21—22). 
x ) The bone m of Woodward’s description of 1907 (1907 a, p. i36, PI. VIII, figs. 2, 8) and x of his description 
1909 (p. 176, PI. XXXV, fig. 9; PI. XXXVII, fig. 5), may, I suppose, be the homologue of the autangular. 
Stensio, Triassic Fishes from Spitzbergen. 10 
