CONTENTS OF No. 204 -New Series. 



MEMOIRS : 



PAGE 



The Development of the Head-muscles in Gallus domesticus, and 

 tlie Morphology of the Head-muscles in the Sauropsida. By F. H. 

 Edgewokth, M.B., D.Sc, Professor of Medicine, University 

 College, Bristol. (With 39 Text-figures) . . . 511 



The Development of Ophiothrix fragilis. By E. W. MacBride, 

 M.A., D.Sc, E.R.S., Professor of -Zoology in McGill University, 

 Montreal. (With Plates 31—36, and 4 Text-figures) . . 557 



On the Segmentation of the Head of Diplopoda. By Margahet 

 BoBiNSON, University College, London. (With Plate 37, and 

 6 Text-dgures) . . . . . .607 



The Fixation of the Cypris larva of Sacculina carciiii (Tiiompson) 

 upon its Host, Carcinus msenas. By Geoffrey Smith, M.A., 

 New College, Oxford. (With 6 Text-figures) . . .625 



Physiological Degeneration in Opalina. By C. Clifford Dobell, 

 B.A., Scholar of Trinity College, Cambridge. (Wilh Plate 38, and 

 2 Text-Ggures) . . . . . .633 



Some Facts in the Later Development of the Frog, Rana tenipo- 

 raria. — Part I. The Segments of the Occipital llegion of the 

 Skull. By Agnes I. M. Elliot, B.Sc., Associate of Newuham 

 College, Cambridge. (With Plates 39 and 40) . . 647 



With Title, Contknts, and Index to Vol. 51. 



