CONTENTS OF No. 229.-New Series. 
MEMOIRS : 
PAGE 
The Structure and Development of Reissner’s Fibre and the Sub- 
commissural Organ. Part 1. By George E. Nicholls, B.Sc., 
F.L.S., Professor of Biology at the Agra College, University of 
Allahabad. (Fi-om the Zoological Department, King’s College, 
University of London.) (With Plates 1-5 and 8 Text-figures) . 1 
Loxosoma loxalina and Loxosoma saltans — Two New Species. 
By Richard Assheton, M.A., Lecturer on Biology in Guy’s Hospital, 
University of London. (With Plates 6 and 7 and 4 Text-figures) . 117 
Gastrulation in Birds. By Richard Assheton, M.A., Lecturer on 
Biology in Guy’s Hospital, University of London . . 145 
Studies in the Experimental Analysis of Sex. Part 9. — On Spermato- 
genesis and the Formation of Giant Spermatozoa in Hybrid 
Pigeons. By Geoffrey Smith, M.A., Fellow of New College, 
Oxford. (With Plate 8) . . . . . 159 
Notes on Sporozoa. Nos. II, III, and IV. By H. M. Woodcock, 
D.Sc., Lister Institute of Preventive Medicine, London. (With 
Plates 9 and 10) : — 
II.— Observations on Karyolysus lacertce (Danil.), and 
Remarks upon other Haemogregarines of Lizards . . 172 
III. — Comparison of the Nuclear Condition in Haemogregarines 
with that in Certain Coccidia .... 196 
IV. — The Nuclear Structure of Leucocytozoon and Hal- 
teridium ...... 215 
The Dorsal Vibratile Fin of the Rockling (Motella). By J. Stuart 
Thomson, Ph.D., F.L.S., F.R.S.E., Lecturer and Senior Demon- 
strator in Zoology, University of Manchester. (With Plate 11) . 241 
