. Bulletin of the British Museum (Natural History), Geology. . Fig. 34 Histionotus angularis Egerton. Restoration of skull roof. The probable medial limit of the dermopterotic is indicated by dashed lines; the nasals are omitted, x 4^ approx. which passed the lateral part of the supratemporal commissure, where it was exposed by a large fenestration. The main lateral line continued anteriorly through the dermopterotic; the form of this bone is obscured by crushing in the specimens. The short postorbital region of the frontal is wide, as usual. The supraorbital sensory canal entered the frontal
. Bulletin of the British Museum (Natural History), Geology. . Fig. 34 Histionotus angularis Egerton. Restoration of skull roof. The probable medial limit of the dermopterotic is indicated by dashed lines; the nasals are omitted, x 4^ approx. which passed the lateral part of the supratemporal commissure, where it was exposed by a large fenestration. The main lateral line continued anteriorly through the dermopterotic; the form of this bone is obscured by crushing in the specimens. The short postorbital region of the frontal is wide, as usual. The supraorbital sensory canal entered the frontal laterally, behind the orbit, and passed medially; the canal in the supraorbital region is exposed by one or two elongated openings (Fig. 34), much as in Propterus. In the preorbital region the frontals form an open trough for the sensory canal as in they do all macro- semiids. They also form two lateral, vertical extensions on either side of the preorbital region of the skull; the frontals are similarly formed in Notagogus. Ganoine is restricted to two regions of the frontal. The smaller patch occurs close to the posterior border, while elongated rugae cover the surface between the orbital embayment and the sensory canal (Woodward 1918 : pi. 17, fig. 3). The nasals are not preserved in the specimens. The orbitosphenoid is better known in H. oberndorferi described below; the remainder of the braincase remains unknown. (iii) Circumorbital bones. There are five large supraorbitals, of which the foremost is the longest and tapers anteriorly. The remaining four are approximately rectangular; all bear a complex pattern of ridges on their surfaces. The remains of the nine infraorbitals are discernible in P577; Woodward did not recognize them. The antorbital is crushed, but appears to have formed the usual tapering tube. The infra- orbitals display the typical macrosemiid configuration; the first seven below the eye are curled over the infraorbital sensory canal, and the two behind the
Size: 1248px × 2002px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
