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Show 1901.] REPTILES FROM PATAGONIA. 183 Cretaceous period '. It is also known that the mud-fish Ceratodus, which now survives in Queensland rivers and once lived in Patagonia", belongs to a race which was cosmopolitan in the Jurassic period. In these two cases, Australia and South America are proved to be merely remote refuges for old types which have been lost by extinction elsewhere. It is therefore just possible that, if the direct ancestors of Miolania were known, this remarkable Chelonian would prove to have originated not on any old Antarctic continent, but in some other region of the globe from which scattered survivors wandered into the lands now named South America and Australia respectively. EXPLANATION OF THE PLATES. PLATE XV. Miolania argentina (pp. 170-172); cranium, upper aspect, one-third nat. size.-From Red Sandstone, Chubut, Argentine Republic, occ., occipital crest; orb., orbit; r.-v., bony bosses. PLATE XVI. Miolania, argent ina (p. 172); same cranium, lower aspect, one-third nat. size, bs., basispbenoid ; i.pt., interpterygoid vacuity ; ot., otic bones ; p.na., palato-nares ; pt., pterygoid ; r., palatal ridge; s.occ, supra-occipital ; other letters as above. • PLATE XVII. Fig. 1. Miolania argentina (p. 171); same cranium with imperfect mandible, right lateral aspect, one-half nat. size, au., auditory opening ; na., anterior nares; s., hinder limit of horny beak; other letters as above. 1 a. Ditto; oral aspect of mandible, one-half nat. size. PLATE XVIII. Fig. 1. Miolania argentina (p. 173); right scapula, imperfect proximally, one-half nat. size. t„ tuberosity. 2. Ditto ; bony ring of tail-sheath, posterior and right lateral (2 a) aspects, one-third nat. size. 3. Genyodectes serus (p. 179); premaxillae, anterior aspect, one-half nat. size.-From Red Sandstone, Chubut. PLATE XIX. Fi$r 1 Genyodectes serus (p. 179); imperfect jaws, right lateral aspect, one-nat. size, d., dentary ; mx., maxilla; pmx., premaxilla. la Ditto- two mandibular teeth of same specimen in position, inner aspect, nat. size, d., dentary ; spl., anterior splenial extension. i A. Smith Woodward, Catalogue of Fossil Fishes in the British Museum, PVF'.Sghm^S^opSaeologico-Paieoncotogica-Suplem. (1899), p. 10. 13* |