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Show 448 DR. W. G. RIDEWOOD ON THE CRANIAL [Dec. 13, 5. On the Cranial Osteology of the Clupeoid Fishes. By W . G. R i d e w o o d , D.Sc., F.Z.S., Lecturer on Biology at St. Mary's Hospital Medical School, London. [Received November 11, 1904.J (Text-figures 118-143.) I n tr o du c tio n. In the spring of 1896, Prof. G. B. Howes suggested to me that an investigation on the structure of the skull in the lower Teleostean fishes would be a profitable piece of research, since there was every prospect of the results proving a valuable means of testing the validity of the existing schemes of classification of the fishes in question, and because an accurate knowledge of the structure of the skull in the lower Teleostean fishes was essential to a successful study of the remains of those extremely interesting extinct fishes which lie on the boundary-line between the Teleosteans and the Ganoids. The investigation has proceeded slowly and intermittently, owing to repeated interruptions and to pressure of other work ; but sufficient progress has now been made to allow of the publication of some of the results. Descriptions of the skulls of Elops, Megalops, and Albula, together with some general observations on the Teleostean skull, have already appeared in the ‘ Proceedings of the Zoological Society,' 1904, ii. pp. 35-81, and observations on the cranial osteology of the Mormyridse, N'otopterida?, and Hyodontidse in the Journal of the Linnean Society, xxix. 1904, pp. 188-217. A third paper, on the skull of the Osteoglossidse, Pantodontidse, and Phractohemidae, has just been completed, and has been offered to the Linnean Society; the present contribution deals with the skull of the Clupeoid fishes. Eleven genera are considered in this paper, namely :-Chiro-centrus, Clupea, Pellona, Pellonula, Pristigaster, Hyperlophus, Chatoessus, Dussumieria, Engraulis, Coilia, and Chanos. A " Summary " of the observations and some " Comments " thereon are given on pp. 488-493. Skulls of Chirocentrus, Clupea, Chatoessus, Engraulis, Coilia, and Chanos were specially prepared for the purposes of the investigation, and were disarticulated according to the method explained in the ‘ Proceedings of the Zoological Society,' 1904, ii. p. 36; the other skulls examined are the property of the British Museum, and I take this opportunity of acknowledging my indebtedness to Mr. G. A. Boulenger for offering to me every facility in his power for the examination of the skulls under his charge. C hirocentrus d o r a b . The only published figure of the skull of Chirocentrus that I have been able to discover is a not very serviceable sketch of |
