TRIASSIC FISHES FROM SPITZBERGKX 
59 
some of its branches. That there can be no question of the nerve as a whole (cf. Huxley, 
1866, p. 35; Reis, 1892, p. 21), seems to be shown partly by the rather slight width of 
the canal and partly by its position in relation to the fossa hypophyseos, as it is 
difficult to imagine the ramus maxillaris and mandibularis or the nervus ophthalmicus 
lateralis with a course of this sort. On the other hand the ramus profundus or a 
branch that is somewhat equivalent to this' can often have its exit far forward, in 
front of the other trig-eminal branches, sometimes together with or immediately behind 
the oculomotorius (Allis, 1897a, pp. 532—534; 1909a, pp. 80— 83 ; Gaupp, 1911, p.419; 
Veit, 1907, p.162, fig. 2, p.187; 1911, p.2o3; Lehn, 1918, figs. 2—4, pp. 353—355, pp. 3 gi— 3 g 3 ; 
Pinkus, 1895, pp. 296—299; Bridge, 1898, pp. 347—348; van Wijhe, 1882, p. 299). Conse¬ 
quently in my opinion it seems rather probable that in this case we are concerned 
with the canal for the r. ophthalmicus profundus. 
Immediately behind the proximal part of the process e there now follows in 
Wimania sinuosa a broad but distinct sinus in the latero-dorsal edge of the basisphenoid 
corpus ( V 2 , 3 text figs. 19, 20; PI. 4, fig. 1; PI. 5, fig. 1). If my explanation of the cranium 
is correct in other respects this sinus has formed the ventral boundary of the foramen, 
through which the ramus maxillaris, r. mandibularis and the ophthalmicus trigemini as 
well as the n. ophthalmicus lateralis had their exits. In any case this foramen, or, if 
two or three foramina were present, these foramina, ought to have been situated in the 
cartilaginous part immediately above this incisure (cf. Bridge and Pinkus). It is certain 
that a comparison with other Teleostomes and with Tetrapods as well would also 
support this view with regard to the relations of the branches of the trigeminus. 
Thus in Polypterus (Lehn, 1918, loc. cit.; van Wijhe, 1882, PI. XV, fig. 6) the foramen 
of the ramus maxillaris and mandibularis trigemini lies immediately behind the sphenoid, 
and a special foramen for the ophthalmicus lateralis is situated a little above and some¬ 
what in front of the former, but in the sphenoid. In Amia (Allis, 1897 a, pp. 591 — 614) 
the foramen for the truncus maxillo-mandibularis is found considerably in front of the 
prootic anteriorly bounded by the alisphenoid and posteriorly by cartilage. The ophthal¬ 
micus lateralis in Amia has its exit by a special foramen in the alisphenoid above that of the 
truncus maxillo-mandibularis. In Lepidosteus (Veit, loc. cit.) there is a single foramen 
developed for all the branches of the trigeminus with the exception of the profundus. 
The foramen for the latter is surrounded by the anterior part of the prootic and this 
is also, as a rule, the case in the Teleostei. As we shall find below in the description 
of the Palaeoniscids, the exit of the trigeminal branches is bounded, at least in certain 
forms, to a considerable extent by a large sphenoid. In the Stegocephalians (Huene, igi 3 , 
pp. 320—322; Watson, 1916, pp. 612—618; 1919; pp. 22—29; Abel, 1919, pp. 23g—243) 
and among reptiles, at least in Lacertilians and Rhynchocephalians, the ramus maxillaris 
and mandibularis trigemini have their exits in front of or above the anterior part of 
the prootic in close relation to or in contact with the upper portion of the basisphenoid 
(cf. Gaupp, 191.1). In Mammalia these trigeminal branches penetrate the ala magna. 
As I shall show in more detail later, the palatoquadrate of W. sinuosa and other 
Coelacanthids articulates with the process e on the basisphenoid. This process thus 
corresponds, at least functionally, to a basipterygoid process. In relation to the cranial 
cavity itself it occupies a somewhat normal position, but is situated, on the other hand, 
8* 
