. Bulletin of the British Museum (Natural History), Geology. 166 PALAEONISCOID FISHES AND THE CHONDROSTEI normal single pair of bones, is somewhat larger than in the average palaeoniscoid. The postero-dorsal surface of each extrascapular is peculiarly scalloped. The parietals are almost square while the lateral wall of the skull roof is composed of a short, broad, dermopterotic, but the position and extent of the dermosphenotic is not clear on any of the specimens. Fric (1893, pis. 109-112) in his interpretation of the skull roof indicated a true fossa in the region of the junction between the
. Bulletin of the British Museum (Natural History), Geology. 166 PALAEONISCOID FISHES AND THE CHONDROSTEI normal single pair of bones, is somewhat larger than in the average palaeoniscoid. The postero-dorsal surface of each extrascapular is peculiarly scalloped. The parietals are almost square while the lateral wall of the skull roof is composed of a short, broad, dermopterotic, but the position and extent of the dermosphenotic is not clear on any of the specimens. Fric (1893, pis. 109-112) in his interpretation of the skull roof indicated a true fossa in the region of the junction between the parietal, frontal and dermopterotic. From a careful study of that region in the specimen concerned I agree with Fric that such a fossa did exist in life and was not caused after death by an otolith as suggested by Westoll (1944 : 65). In this respect Sphaerolepis shows some similarity to Pyritocephalus Fric (Westoll 1944). The frontals are large and the nasals and postrostral long, but the remaining bones constituting the snout region could not be distinguished with any degree of certainty although the position of the nares could be seen. The maxilla is of unusual shape being rounded dorsally as in Pseudogonatodus nov. The teeth on the maxilla are of moderate size (somewhat larger than in the normal palaeoniscoid) and arranged in a single series. The preopercular is almost vertical and much narrower than in most palaeoniscoids and in this respect it also resembles Pseudogonatodus nov. The opercular is more than three times deeper than broad. Beneath the subopercular are some ten branchiostegal rays with a median gular anteriorly. Lower jaw. The angular only occupies a small portion of the jaw surface while the dentary is considerably thickened ventrally and forms the major portion of the outer surface of the jaw. A single row of stout teeth is present on the upper margin of the dentary. The palate. The parasphenoid is short, narrow anteriorly, but expands posteriorly, and in g
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