No. 2.] 



NOTES ON DISTOMUM PATELLARE. 



6 9 



FIG. 4. Part of excretory capillary, showing nucleus. 



3. Flame-cells and Capillaries of the Excretory System . - - I 

 can confirm the work of Schuberg 1:! on these points. The 

 excretory capillaries have a cellular wall of their own, contain- 

 ing large, though widely 

 scattered, nuclei (Fig. 4), 

 and are terminated by 

 closed flame-cells (Fig. 5). 

 No permanent lacunar 

 spaces exist in the paren- 

 chyma, the excretory mat- 

 ter being passed to and 

 through the flame-cells by 

 osmosis. The processes 

 of the protoplasmic part 

 of the flame-cell extend 

 between the parenchyma 

 cells. Deeply staining 

 (muscular?) thickenings 

 are found in the capillary 

 walls. There is a marked 

 resemblance between the nuclei of the giant-cells and those 

 of the capillaries and flame-cells, - - a resemblance which is, 

 perhaps, partly responsible for the observation of excretory 

 capillaries in the suckers, and for other confusion which has 

 existed between the giant-cells, and cells of the excretory sys- 

 tem (see G. Walter, 20 Villot, 21 Mace, 11 Braun 8(a) upon the peri- 

 pheral giant-cells, and Wright and Macallum 22 upon the " renal " 

 cells of Sphyranura). 



ZOOLOGICAL LABORATORY, 

 UNIVERSITY OF CHICAGO, 

 April 20, 1897. 



20 WALTER G.: Beitrage zur Anatomie und Histologie einzelner Trematoden, 

 Arch. f. Naturgesch, Bd. i, 1858. 



21 VILLOT, A.: Organization et developpement de quelques Trematodes endo- 

 parasites marins, Ann. des Sci. A 7 at., tome viii, 1878. 



22 WRIGHT AND MACALLUM: Sphyranura Osteri, Journ. of Morph, vol. i, 

 1887. 



FIG. 5. Flame-cell. 



