ON WANDERING CELLS IN ECHINODERMS. 81 
On Wandering Cells in Echinoderms, &c., 
more especially with Regard to Excre- 
tory Functions. 
By 
Herbert E. Durham, M.A., 
King’s College, Cambridge, and Guy’s Hospital, London. 
With Plate I. 
INTRODUCTORY. 
Tue following observations have been made partly during 
two visits to the Marine Laboratory at St. Andrews (July and 
August, 1887, and March and April, 1888)—for the facilities 
there offered and for every kindness I have to thank Professor 
M‘Intosh ; partly in the Morphological Laboratory at Cam- 
bridge, thanks to the indulgence of Mr. Sedgwick, during the 
Michaelmas Term, 1888, when fresh material obtained from 
Jersey and that preserved at St. Andrews were examined ; 
partly also at home, living material being obtained from the 
Laboratory of the Marine Biological Association at Plymouth, 
for sending which I must here tender my thanks to the 
director and his assistants. 
Lastly, I must thank the late Dr. P. H. Carpenter for his 
kindness and ever ready advice, as well as Mr. 8. F. Harmer 
for criticism and for references. 
The following forms have been used during the investi- 
gation : 
VOL. XXXIII, PART I.—NEW SER. F 
