V 



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13. On two new Elasmobranch Fishes (Crossorhinus juras- 



sicus, sp. nov., and Protospiuax annectans, gen. et sp. 

 nov.) from the Upper Jurassic Lithographic Stone 

 of Bavaria. By Arthur S ith Woodward, LL.D., 

 F.R.S., V.P.Z.S. (Plate I.) 231 



14. The Function of Pathological States in Evolution. By 



Morley Roberts 237 



15. Notes on the Beavers at Leonardslee, 1916-1918. By 



Sir Edmund G. Loder, Bart., Yice- President Z.S. ... 255 



16. On the Madagascar Frogs of the Genus Mantidactylus 



Blgr. By G. A. Boulenger, F.R.S., F.Z.S 257 



17. Ciliary Action in the Internal Cavities of the 



Ctenophore Pleurobrachia pileus Fa.br. By James 

 F. Gemmill, M.A., M.D., D.Sc, F.Z.S. (Text- 

 figures 1 & 2.) 263 



18. On Seymouria, the most primitive known reptile. By 



D. M. S. Watson, M.Sc, Capt. R.A.F., Lecturer 

 in Vertebrate Paleontology, University College, 

 London. (Text-figures 1-15.) 267 



Alphabetical List of Contributors vii 



Index xi 



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