23O JAMES ERNEST KIXDRED. 



Perivisceral fluid from individuals of each of the above species 

 was drawn from the perivisceral cavity and studied by the hang- 

 ing drop method. In studying the phagocytic activity of the 

 cells, a concentrated suspension of finely granulate carmine or 

 india ink in seawater was used. This suspension was injected 

 into the perivisceral cavity through a minute opening in the body 

 wall by means of a delicate hypodermic needle. The amount of 

 suspension injected varied with the size of the animal, but it was 

 found that the usual dose sufficient to affect the phagocytes was 

 8 cc. The injected animals were kept in a live box for a day, so 

 that there would be time for thorough ingestion of the particles. 



The clotting activities of the cellular elements were studied in 

 drops of perivisceral fluid which had been allowed to stand for 

 varied lengths of time. 



A saturated solution of seawater and methylene blue, another 

 of seawater and neutral red were made and allowed to stand for 

 several days before using. The supernatant solution which was 

 free from particulate matter was decanted off and the solution 

 used drop for drop with the perivisceral fluid. These stains were 

 used for intravitam staining in certain phases of the investigation 

 since they were found to be specific for the vacuoles of the leuco- 

 cytes. 



II. OBSERVATIONS. 



i . The Leucocytes. 



In his paper on the leucocytes of the invertebrates, Goodrich 

 ('19) called attention to the fact that the leucocytes of Asteracan- 

 thion glacialis are characterized by the presence of extensive mem- 

 branous processes of the ectoplasm. He says, "The freely pro- 

 jecting pseudopodia usually described are either figured from 

 optical sections of the folded membranes or from cells which have 

 produced them under abnormal conditions. These pseudopodia 

 may be present on cells in the fluid withdrawn from the body and 

 which has been allowed to stand, and are probably derived from 

 preexisting membranes." Goodrich calls all of the cells leuco- 

 cytes, making no distinctions. 



In Arbacia (Kindred, '21) I observed the formation of a syncy- 

 tium in the perivisceral fluid by the anastomosis of filiform proc- 

 esses which had been derived from the membranous flaps of the 



