556 



DR. F. E. BEDDARD ON 



with quite similar nuclei. Furtbermove, tlie nuclei (see text-fig. 

 87, p. 554) do not give the impression that they line the cavities ; 

 they belong rather to the tissue of the walls ; there are, moreover, 

 often considerable tracts without any nuclei at all, as is often 

 the case with the medullary tissue of tapeworms. This is, of 

 course, opposed to the idea of a lining membrane. 



Text-fie-. 89. 



■ m. 



9 V 



• O 



Dipylidhm dongolense. 



A portion of a section througli a proglottid less mature tlian that represented 



in text-figs. 86 & 87. 



m. Longitudinal muscles, o. Egg-holding spaces. 



All this contrasts greatly with the uterine spaces of D. caninum 

 (see text-fig. 88, p. 555), where there is invariably a close row 

 of nuclei with accompanying protoplasm actually lining the 

 cavity and in which the nuclei of the medullary tissue are 

 not numerous and, as a rule, different from those of the lining 

 membrane. The medulla, in fact, forms a reticulum in the 

 meshes of which lie the developing embryos ; there is not, 

 at any rate in the fully mature stage, any uterus at all, A 



