No. I.] SPHYRANURA OSLERT. 1 9 



Sphyranura which can be considered as similar to them, and it 

 was consequently with interest that we turned to the account of 

 the body-parenchyma in other monogenetic Trematodes to 

 ascertain whether they had been detected there. Taschen- 

 berg's account of that tissue in Tristomum is the most satisfac- 

 tory one, and he states that his later observation of On- 

 chocotyle confirms his views. According to this author ^ the 

 parenchyma of the adult is a reticulated matrix, containing 

 protoplasm formed at the expense of the plasma of certain 

 cells, the nuclei of which are found scattered in the matrix; 

 while other cells, whose plasma has not undergone this change, 

 are found free within cavities of the matrix. He considers that 

 the latter elements are the plant-like cells of Leuckart, and that 

 what has been interpreted as the membrane of the plant-like 

 cell is in reality the boundary of the matrix cavity. It is pos- 

 sible that these plant-like cells of Taschenberg are the vesicular 

 cells of the recent authors, but their description does not cor- 

 respond to anything we have met with in Sphyranura. 



The connective tissue or parenchyma in Sphyranura is com- 

 posed of branching cells, forming a mesh-work, the size of the 

 meshes varying in different parts of the body. In the caudal 

 region these cells are closely packed together, and leave 

 between them but little interspace, except in the neighborhood 

 of the looping of the larger excretory trunks posterior to the 

 intestinal anastomosis. These cells answer to those of the first 

 kind described by Looss and Kerbert. Their processes, evi- 

 dently elastic, are homogeneous, not stainable, and the rela- 

 tions of these can only be determined with highly magnifying 

 powers. The cells themselves vary slightly in size, measur- 

 ing 12-22 ^, and have either an oval or spherical shape or an 

 irregular form. The nucleus fills out the greater part of the 

 cell-body, there being but little or no protoplasm surrounding 

 it; it stains slightly as a whole where its granular character is 

 not pronounced ; in this case there is one or more chromatin 

 nucleoli and a nuclear net-work is commonly visible. This net- 

 work is sometimes of a coarse character, especially if granules 

 are absent, when the chromatin is gathered into one or two 

 large nucleoli. When the nucleus stains vividly its contents 

 are finely granular; at the same time the protoplasm about 

 ' Beitrage, p. 12. Weitere Beitrage, p. 8. 



