58 ERIK A : SON STENSIO 
As we have seen, the basisphenoid corpus is considerably high. The floor of the 
cranial cavity is situated above it on a level with the dorsal part of the process f h on 
the prootico-opisthotic (text figs. 19, 20, 22). Immediately in front of the basisphenoid 
corpus there then follows the deep fossa, open at the front and dorsally, that has just 
been described, and behind the same corpus the floor of the cranial cavity seems also 
to have sloped downwards, though not so rapidly. According to Heineke’s view (1907, 
p. 8) the fossa hypophyseos followed in front of the basioccipital, and the unossified 
gap in the cranial base in front of this bone is termed by him the hypophyseol fenestra. 
With the interpretation I have given above of the different bones in the species 
described here, the fossa hypophyseos should, if Heineke’s view were correct, be 
bounded by the basisphenoid anteriorly, the prootico-opisthotic laterally and the basi- 
occipital posteriorly when the latter bone is developed. It is clear, however, without 
further discussion that this view is not tenable. The forward opening fossa on the basi¬ 
sphenoid seems instead to have such a special shape and otherwise to. be in such a 
position that it has undoubtedly had some relation to the hypophysis and the ventral 
parts of the diencephalon in general. Thus the corpus of the basisphenoid would be 
situated behind the hypophysis in the same way as the corpus of the corresponding 
bone in Stegocephalians and reptiles. In other words the basisphenoid corpus probably 
belongs to the chordal part of the neurocranium. 
Apart from the basisphenoid and the above-mentioned process (Alsph) from the 
dermal cranial roof, by far the greater part of the rest of the orbitotemporal region 
in Wimania might have consisted, as in other Mesozoic Coelacanthids, principally of 
cartilage (text fig. 19), which was attached to the corpus and the lamellae of the basi¬ 
sphenoid. The ventral processes (v) on the same bone are so even and smooth at the bottom 
on the anterior side that it looks as if the cartilage had not joined them at this surface, 
but that a fenestration had been present under the fossa hypophyseos of about the same 
extent as I have tried to indicate in text fig'. 19 (fen), The cranial cavity has certainly 
extended a considerable distance in front of the basisphenoid, probably as far as to 
the ethmoidal region, which was also the case in Dictyonosteus (Stensio, 1918 c). 
Judging from the size of the eye, the optic nerve (II) must have been strong. It 
has penetrated into the orbit probably fairly far forward, in about the way I have 
hypothetically marked in text fig. 19. In the same figure I have also hypothetically 
drawn the foramina for n. trochlearis (IV) and n. oculomotorius (III), which nerves 
must both have emerged into the orbit in front of the basisphenoid. 
The above mentioned paired canal, which passes from the postero-dorsal part of 
the fossa hypophyseos (V lt ) through the lamellae of the basisphenoid in an antero¬ 
lateral direction and whose outer opening (V lc ) is situated somewhat ventrally and 
antero-medially of the process e, has its exact equivalent in Dictyonosteus in the canal 
that I have there indicated by the letters fo (Stensio, 1918 c, PI. VI). Latero-caudally 
of this foramen there follows in Dictyonosteus the process Bp, which probably corresponds 
to e in Wimania and other Coelacanthids, although it is situated lower than in these. 
The relation of the canal to the fossa hypophyseos is also similar in both cases. 
It seems rather probable that the canal in question both in Dictyonosteus and in the 
Coelacanthids was traversed by the trigeminus nerve or, more correctly speaking, by 
