. Bulletin of the British Museum (Natural History), Geology. 270 EVOLUTION OF THE SNOUT IN ACTINOPTERYGIANS The paired fins and their girdles. The primary girdle is ossified, both the scapulocoracoid and mesocoracoid regions being apparent. Specimen shows clearly four radial elements (Text-fig. 3). The second radial from the lateral edge of the fin is hour-glass shaped, whilst the two innermost members are stout and almost straight rods. DistaUy the first two radials (numbering from the lateral edge) articulate with four smaller ossifications ; these probably represent the os
. Bulletin of the British Museum (Natural History), Geology. 270 EVOLUTION OF THE SNOUT IN ACTINOPTERYGIANS The paired fins and their girdles. The primary girdle is ossified, both the scapulocoracoid and mesocoracoid regions being apparent. Specimen shows clearly four radial elements (Text-fig. 3). The second radial from the lateral edge of the fin is hour-glass shaped, whilst the two innermost members are stout and almost straight rods. DistaUy the first two radials (numbering from the lateral edge) articulate with four smaller ossifications ; these probably represent the ossified distal cartilages of the radials. The third radial articulates directly with six lepidotrichia and the fourth probably with three lepidotrichia. The lepidotrichia number about nineteen, and they are jointed throughout their length except at the bases of the first two rays of the lateral margin. The lepidotrichia are delicately ornamented with two distinct ridges anteriorly, which run along the length of the ray, and posteriorly with short diagonal ridges of enamel that run from about the mid-line out and away from the fin base, to the posterior edge of the 10mm Fig. 3. Cosmoptychius striatus (Agassiz). Reconstruction of pectoral girdle. Mainly from The pelvic fin is very long based with about forty to forty-five fin rays, and similar ornamentation to the pectorals, except that instead of two ridges of enamel running lengthways along the rays anteriorly there is only one. Both pectoral and pelvic fins bear fulcral scales. The unpaired fins. Both dorsal and anal fins are triangular, the dorsal being somewhat the larger. Both have about forty lepidotrichia and are fringed anteriorly by pointed fulcral scales. The ornamentation of these two fins is essentially similar to that on the pectoral as far as the anterior fin rays are concerned, but on the more. Please note that these images are extracted from scanned page images that may have been digitally
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