Page 



13. On two new Elasniobranch Fishes {Crossorhinus juras- 



sicus, sp. nov., and Protospiiiax annectaii,s, 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., Vice-President Z.S. ... 255 



16. On the Madagascar Frogs of the Genus Mantidactyhis 



Blgr. By G. A. BouLENGER, F.R.S., F.Z.S '..... 257 



17. Ciliary Action in the Internal Cavities of the 



Ctenophore Flerr.robrachia pileus Fabr. 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 Palaeontology, University College, 

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



Alphabetical List of Contributors vii 



Index .^ , xi 



