138 TEANSACTIONS 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 ot 

 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 J° 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 severing the 

 rays from the disc, into 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 

 give a brief account of the hgemal* 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 



* Agreeing with Durham I regard this term as more appropriate than 

 ' blood vascular," 



