484 Mr. C. T. Regan on the Origin and the skull. As he gives the number of vertebrae as 21 it seems probable that in tlie preparation of the skeleton tlie first vertebra adhered to the cranium, and was then removed separately and perhaps lost. Subfamily 2. Caproinm. Mouth extremely ])rotractile; prsemaxillary processes very long, separating the frontals and extending back beneath the supraoccipital ; maxillary narrow, without supramaxillary ; a broad subocular shelf. Spinous dorsal not shorter than the soft-rayed fin. The Miocene Proantigonia, Kramberger, is closely allied to the recent Capros, Lacep. LIV. — The Origin and Evolution of the Teleostean Fishes of the Order Heterosomata. By C. Tate Regan, M.A. (Published by permission of the Trustees of the British Museum.) I'he Heterosomata, or Flat-fishes, differ from all other fishes in their asymmetry ; both eyes are on one side, which is coloured, whilst the eyeless side is usually white. Fi-1. B. Disarticulated frontal bones of (A) Halibut {Hijypogloasus hippoghssus) and (Bj Plaice (Pleuronedes platessa). (After Traquair.) pfa, praefrontal articulation ; ip, iuterorbital process ; t, interorbital bar. In the skull of all flat-fishes there is a bony interorbital bar mainly formed by the interorbital portion of the frontal bone 4
BioStor
