232, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
My thanks are due to Prof. Marshall for placing at my 
disposal the resources of the Owens College Zoological 
Laboratory, and for his ever ready kindness and advice; 
also to Mr. R. Standen of the same Laboratory, for the 
readiness and goodwill with which he has assisted me in 
the preparation of my material, nearly the whole of which 
has been collected at various points within the marine 
area of the Liverpool Marine Biology Committee. To 
that Committee my thanks are tendered for the facilities 
afforded by the Marine Biological Station at Port Erin 
for the examination and preservation of the material col- 
lected in that neighbourhood. With regard to methods 
of preservation, I must admit that mine have not been in 
error on the side of refinement. Previous experience of 
the slowness with which osmic acid penetrates, and the 
brittleness which it produces, led me to neglect the use 
of this otherwise valuable re-agent. In nearly every case 
my specimens were fixed with saturated solution of corro- 
sive sublimate, care being taken to expose well the parts 
required for sectioning. Decalcification was effected by 
immersion in 10 ,/° solution of nitric acid for about 24 
hours, more or less according to the size of the specimen. 
In one case I put the living starfish, after severmg the 
rays from the disc, mto the nitric acid solution, and 
hardened it in alcohol afterwards. This method is not 
without its value on account of the extremely small amount 
of contraction produced. Before discussing the results of 
my own work and that of my predecessors, I propose to 
ceive a brief account of the hemal* and water-vascular 
systems of the Asteroidea, and of such other structures as 
are in relation thereto. In this way I hope to make the 
* Aoreeing with Durham I regard this term as more appropriate than 
‘* blood vascular.” 
