. Bulletin of the British Museum (Natural History) Geology Supplement. ESPECIALLY MYCTOPHOIDS 173 a small anterior expansion in advance of the first uroneural, which may well represent the neural arch of ural vertebra one. If this is the case then the forerunner of a stegural is present in the elopoids. In the Salmoniformes the epurals are associated with the dorsal edge of the stegural. In Elops and Ichthyotringa the epurals contact the dorsal edge of the anterior expansion of uroneural one. This possibly affords further evidence that the anterior expansion is the forerunner of a true stegura
. Bulletin of the British Museum (Natural History) Geology Supplement. ESPECIALLY MYCTOPHOIDS 173 a small anterior expansion in advance of the first uroneural, which may well represent the neural arch of ural vertebra one. If this is the case then the forerunner of a stegural is present in the elopoids. In the Salmoniformes the epurals are associated with the dorsal edge of the stegural. In Elops and Ichthyotringa the epurals contact the dorsal edge of the anterior expansion of uroneural one. This possibly affords further evidence that the anterior expansion is the forerunner of a true stegural. n. a. pul pu4. 5mm Fig. 80. Elops sanrns. Caudal fin skeleton in lateral view. Preural vertebra two in Ichthyotringa has a complete neural spine. In Elops this neural spine is reduced (Text-fig. 80), as it is in certain salmonoids (Norden, 1961; pi. 14, fig. G, Coregonus artedii). In other salmonoids the neural spine is complete (Text-fig. 81). In those forms in which a reduced neural spine occurs then three separate epurals are normally seen (the primitive teleostean number according to Patterson, 1968a : 220). Ichthyotringa, with its complete neural spine on preural vertebra two, has only two epurals. It would seem possible, then, that the anterior- most epural, when three are present, comes from the neural spine of preural vertebra two, the remaining two epurals being the neural spines of preural vertebra one and ural vertebra one. Patterson (1968a : 221) has drawn attention to the fact that the foremost epural can " fuse with a neural arch so that it is indistinguishable from a neural spine ". It is equally possible that this is what has occurred in Ichthyo- Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London : BM(NH)
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