ON FECUNDATION, MATURATION, AND FERTILISATION. 315 
Notes on the Fecundation of the Egg of Sphe- 
rechinus granularis, and on the Matura- 
tion and Fertilisation of the Egg of Phallusia 
mammillata. 
By 
M. D. Hill, B.A.Oxon., 
Assistant to the Professor of Zoology in the Owens College, Manchester. 
With Plate 17. 
Ir is somewhat remarkable that since the late Professor Fol’s 
(4) account of the “ Quadrille des Centres” in the Echinoderm 
egg, up till very recently, no further work had been published 
either to confirm or refute Fol’s original statements. It is 
therefore with all the more satisfaction that zoologists will 
welcome the conjoint paper of Messrs. Wilson and Matthews 
(10), being, as it is, a record of so much careful and accurate 
work. To the student of cytology, however, the theoretical 
importance of a clear insight into the complicated phenomena 
accompanying the maturation and fertilisation of ova is so 
great, that all evidence gained from independent work, with 
- the help of reliable optical instruments and the most fitting 
reagents, necessarily becomes of some interest. I propose, 
therefore, to give in this paper an account of a portion of the 
work done by me whilst holding the British Association’s table 
in the Marine Zoological Station at Naples. I have, however, 
to regret that circumstances forced me to leave Naples before 
I had completed my observations, especially on the maturation 
of the sexual cells in Phallusia mammillata. In all cases 
where a doubt still exists as to the real facts, I have been careful 
to state so expressly. My thanks are due to the British 
