16 UPPER CRETACEOUS TELEOSTS 
canal from the preoperculum. The tube in the pterotic opens posteriorly in a shallow 
groove above the opening of the post-temporal fossa. The posterior end of the fossa 
is roofed by the supratemporal bone which transmitted the lateral line canal into the 
rear end of the pterotic. 
The parietals are prominent oblong bones meeting in the mid-line in a sinuous 
suture. Anteriorly the parietals are overlapped by the frontals and laterally by the 
pterotics. The posterior edges of each parietal are obliquely arranged so that they 
meet in the mid-line in a shallow V-shaped indentation. Attached to the rear edge 
of both parietals are small transverse strips of bone each having a grooved dorsal 
surface. These slips of bone appear to be the remnants of the transverse limbs of the 
supratemporal. The main part of the supratemporals are small and positioned 
laterally. The supratemporal sensory canal ran across the skull-roof through both 
supratemporal bones and across the dorsal surfaces of the parietals and on to these 
reduced slips of bone. 
The supraoccipital is small, just appearing on the roof of the skull. The antero- 
dorsal extent of the supraoccipital is covered by the parietals. A small supra- 
occipital crest extends from the posterior face of the bone, but does not rise above the 
plane of the skull-roof. The supraoccipital contacts the epiotics laterally in a 
straight suture. 
The epiotics extend postero-laterally from the supraoccipital and bear slight dorsal 
thickenings for the articulation of the dorsal limbs of the post-temporals. The 
epiotic contacts the parietal anteriorly and forms the postero-medial border to the 
post-temporal fossa. The dorsal surface of the epiotic and the extreme posterior 
regions of both the parietal and the pterotic are covered dorsally by the supra- 
temporal. 
The parasphenoid is straight and considerably expanded laterally. At the an- 
terior end of the orbit the parasphenoid is an extremely wide flat plate of bone. The 
lateral ethmoid limits the orbit anteriorly, arising from the ventral surface of the 
frontal. Ventrally the lateral ethmoid is spread and its medial part appears to 
attach to the dorsal surface of the parasphenoid. More laterally the lateral ethmoid 
is free from the parasphenoid and attaches to the postero-dorsal part of the palatine. 
In the hind wall of the orbit the pleurosphenoid meets the sphenotic, prootic and 
the undersurface of the frontal. Joined to the anterior edge of the pleurosphenoid 
and pressed against the ventral surface of the frontal in the middle of the orbit, 
is another bone which appears to be the orbitosphenoid. Ventral to the pleuro- 
sphenoid a further slip of bone is visible and this may represent the upper end of a 
basisphenoid. 
In front of the orbit overlapping part of the frontal and lateral ethmoid there is a 
thin, small bone which may represent a nasal or a supraorbital. 
Remarks. The remainder of the description of Ichthyotringa delicata will be con- 
fined to those features which differ from Ichthyotringa furcata or which are exhibited 
better. 
The infraorbital bones, below the orbit, are crushed against the palate but show 
appreciably better than in Ichthyotringa furcata. The two infraorbitals below the 
