NOTES ON PARASITES. 



447 



by the relations which it bears to the excretory system and 

 to the reproductive organs. The former are not formed 

 from its walls, and with the exception of certain aberrant 

 species, 1 Lecanocephalus and Dockmius, the latter do not 

 open into its lumen. 



This space contains a corpusculated fluid, and probably 

 it acts to some extent both as a blood-space and as a lymph- 

 space. Within the last year a new light has been thrown 

 on what goes on in the body-cavity of these lowly parasites 

 by Prof. Nasonov 2 of Warsaw, who, utilising the methods 

 of Kowalewsky, has demonstrated the existence in Nema- 



a 



Fig. i. — Anterior extremity of the body of Ascaris mcgalocephala. x. r2. From 

 Nasonov. The interior is exposed by a dorsal incision, two hours after an injection of 

 Indian ink. 



a. The star-like bodies in which the ink particles accumulate. The clear space 

 is the nucleus of the giant cell. 



b. The alimentary canal. 



todes of certain gigantic cells which support others whose 

 function it is to dispose of the foreign bodies which may, 

 from some reason or other, make their way into the body- 

 cavity of these creatures. 



1 Hamann, S&. Ab., Berlin, 1 891, p. 57. 



2 Zool. Anz., Bd. xx., 1897, p. 202, and Arch. Parasit. T. I., 1898, p. 170. 



