. Bulletin of the British Museum (Natural History), Geology. Diagnosis. Histionotus reaching standard length of 150 mm; mean proportions as percentage of standard length: head length 30%, trunk depth 40%, predorsal length 37%, prepelvic length 53%, preanal length 77%; dentary teeth tall and styliform; the two lobes of the dorsal fin close together, with a total of c. 25 rays. HoLOTYPE. British Museum (Natural History), P577. Horizon and Localities. Purbeck Beds of Dorsetshire and Wiltshire, England. Material. BM(NH): 46421, P577, P3614, P5935. Remarks. Woodward (1918 : 77; pi. 17, figs 1-5) ha
. Bulletin of the British Museum (Natural History), Geology. Diagnosis. Histionotus reaching standard length of 150 mm; mean proportions as percentage of standard length: head length 30%, trunk depth 40%, predorsal length 37%, prepelvic length 53%, preanal length 77%; dentary teeth tall and styliform; the two lobes of the dorsal fin close together, with a total of c. 25 rays. HoLOTYPE. British Museum (Natural History), P577. Horizon and Localities. Purbeck Beds of Dorsetshire and Wiltshire, England. Material. BM(NH): 46421, P577, P3614, P5935. Remarks. Woodward (1918 : 77; pi. 17, figs 1-5) has given a detailed account of this species. The material is redescribed below, however, in the light of knowledge gained from other macro- semiid genera. Description, (i) General features. Histionotus angularis is a deep-bodied, laterally-compressed fish; its average proportions are given in the diagnosis above. (ii) Skull roof and braincase. The skull roof is displayed in P5935 and P577 (Fig. 33). The parietal is large and approximately rectangular, forming straight sutures with its fellow, the frontal, and the dermopterotic. The parietal contacts the supratemporal along an identation in its postero- lateral corner. The supratemporal commissure crossed close to the posterior edge of the bone and was exposed dorsally by a small fenestration, as in Propterus. The canal emerged from its tube medially and crossed the midline unenclosed. Anterior to and parallel with the supratemporal commissure lies a short groove which housed the middle pit-line; no other pit-lines are visible. Thick ganoine rugae radiate from this region. The supratemporal is, as usual, small, and does not reach the midline of the skull. Its irregular form is difficult to interpret in the specimens. It appears to have formed a wide thin-walled tube around the cephalic division of the main lateral line, together with a medial portion through A. mnn. Please note that these images are extracted from scanned page im
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