. Bulletin of the British Museum (Natural History), Geology. TCHTHYOKENTEMA PURBECKENSIS 27 P. 8378, and fragments of similar ribs have been observed in the material from Lulworth ; in P. 8378 they appear to have been about 5-5 mm. in length. No traces of intermuscular bones have been found and it seems probable that none was Fig. 12. Ichthyokentema purbeckensis. Reconstruction of trunk vertebra, a, in lateral view, b, in anterior view. Based mainly on P. 44976 and P. 45024. For explanation of lettering see p. 43. (h) Appendicular Skeleton The pectoral girdle is shown in lateral view
. Bulletin of the British Museum (Natural History), Geology. TCHTHYOKENTEMA PURBECKENSIS 27 P. 8378, and fragments of similar ribs have been observed in the material from Lulworth ; in P. 8378 they appear to have been about 5-5 mm. in length. No traces of intermuscular bones have been found and it seems probable that none was Fig. 12. Ichthyokentema purbeckensis. Reconstruction of trunk vertebra, a, in lateral view, b, in anterior view. Based mainly on P. 44976 and P. 45024. For explanation of lettering see p. 43. (h) Appendicular Skeleton The pectoral girdle is shown in lateral view in Text-fig. 6 and in medial view in Text-fig. 13. The extrascapular (esc.) (P. 44963) is a triangular bone, tapering to a point medially. It is uncertain whether or not it met its fellow in the mid-line. The lateral line canal entered the postero-lateral corner of the bone from the supra- scapular, and divided immediately within the bone into the main cephalic canal which passed forwards into the dermopterotic, and the supratemporal commissural canal which passed medially, giving off three or four branches through small pores en route. The suprascapular (ssc.) (P. 44964) is large, and roughly equal in size to that of Pholidophoms similis (Saint-Seine, 1949 : 217). The bone may possibly have met its fellow in the mid-line, and its straight anterior edge fitted against the posterior edge of the extrascapular. The antero-lateral corner of the bone is thickened, and bears a slender process which passes antero-ventrally and was bound to the intercalar by ligaments. The lateral line canal, received from the supracleithrum behind, passed forwards to the extrascapular through a short canal at the extreme lateral edge of the bone. The surface of the suprascapular is ornamented with feeble ridges. The supracleithrum (scl.) (P. 6171 ; P. 44965) is a blade-shaped bone with a thickened anterior edge. The head of the bone bears two projections which articulate with notches on the hind edge
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