CONTENTS. 



CONTENTS OF No. 201, N.S., FEBRUARY, 1907. 



MEMOIRS : PAGE 



On the Parietal Sense-organs and Associated Structures in the New '' 

 Zealand Lamprey (Geotria australis). By Akthue Dendy, 

 D.Sc, E.L.S., F.Z.S., Professor of Zoolofry in King's College 

 (University of London). (With Plates 1 and 2) . .1 



Studies in Spicule Formation. V. — The Scleroblastic Develop- 

 ment of the Spicules in Ophiuroidea and Echinoidea, and in the 

 Genera Antedou and Synapta. By W. Woodland, Demonstrator 

 of Zoology, King's College, London. (With Plates 3 and 4) . 31 



Studies in Spicule Formation. VI. — Tlie Scleroblastic Develop- 

 ment of the Spicules in some Mollusca and in one Genus of 

 Colonial Ascidians. By W. Woodland, Demonstrator of 

 Zoology, King's College, London. (With Plate 5) . . 45 



A Preliminary Consideration as to tiie possible Factors concerned 

 in the Production of the various Forms of Spicules. By W. 

 Woodland, Demonstrator of Zoology, King's College, London . 55 



On Neurosporidiuin cephalodisci, n. g., n. sp., a Sporo- 

 zoon from the Nervous System ofCephalodiscus nigrescens. 

 By W. G. RiDEWOOD, D.Sc, Lecturer in Biology at St. 

 Mary's Medical School, University of London ; and H. B. 

 Fantham, B.Sc, A.R.C.S., University College, Loudon ; Demon- 

 strator in Biology at St. Mary's Medical School. (With Plates 

 6 and 7) . . . . . .81 



Gametogenesis and Fertilisation in Nematus ribesii. By L. 

 DoNCASTER, M.A., late Mackinnou Student of the Royal 

 Society ; Lecturer in Zoology in the University of Birming- 

 ham. (With Plate 8) .... 101 



The MoUuscan Radula: its Chemical Composition, and some Points 

 in its Development. By Igerna B. J. Sollas. (With Plate 9) 115 



Observations on Tooth-Development in Ornitliorliynchus. By 

 J. T. Wilson, Professor of Anatomy, University of Sydney, 

 N.S.W., and J. P. Hill, Jodrell Professor of Zoology, Univer- 

 sity College. Loudon. (With Plates 10—12) . . 137 



