1888.] The Emigration of Corpuscles in the Starfish. 



32, 



January 26, 1888. 



Professor a. G. STOKES, D.C.L., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. " The Emigration of Amoeboid Corpuscles in the Starfish." 

 By Herbert E. Durham, B.A., lately Vintner Exhibitioner, 

 King's College, Cambridge. Communicated by P. Herbert 

 Carpenter, D.Sc, F.R.S., F.L.S. Received January 5, 

 1888. 



[Plate 3.J 



Through the kindness of Professor M'Intosh, to whom my very best 

 thanks are due, I spent some time last summer at the Marine 

 Laboratory at Saint Andrews. 



The results given below arose from what were intended to be 

 control experiments in some observations which aimed at determin- 

 ing, if possible, what organ or system of organs is definitely excretory 

 in function in the Echinoderms. 



The common starfish (Asterias ruhens) was the form used, being 

 convenient both from its size and from its abundance. 



Indian ink or a precipitated aniline blue was injected into the 

 ccelomic cavity by means of a fine pipette or a hypodermic syringe. 

 It was found best to insert the instrument into an arm close to the 

 disk, for then the arm is far more rarely thrown off than if the 

 puncture is made near its distal end. The specimen was next held 

 in different positions so as to distribute the injected fluid. 



The granules that are introduced are ingested by the amoeboid 

 corpuscles which float in the ccelomic fluid, as can readily be 

 demonstrated by microscopic examination of that fluid. The 

 granule-laden phagocytes can be seen very plainly, owing to the 

 particles they have ingested, in the dermal branchiae of a living 

 specimen. The cilia of the ccelomic epithelium cause them to dance 

 up and down in the branchia, and to be thrown against its wall. 

 Every now and again a corpuscle will adhere, and by repetition of 

 this process a small clump may be formed ; this occurs at or near the 

 apex of the branchia. 



2 b 2 



