ENCHYTR^ID^ 37 



glands are large and contain large eosinophil granules (in the figure 

 black). Their ducts are, as usual, long and narrow. They penetrate 

 the atrial wall, surrounded by circular muscles. After entering, a few 

 of them seem to spread out, but the majority remain bunched together, 

 and enter in this manner between the epithelial cells of the atrial 

 lumen. Here the ducts open their contents of eosinophil granules into 

 pockets of large size. These pockets may readily be mistaken for 

 cells, but favorable cuts show that they are entirely independent of the 

 cells, that they do not contain nuclei, and that they stand in direct con- 

 nection with the ducts from the glands, pi. v, fig. 5, which represents 

 a cross-section of the atrium just above the penial bulb, is slightly 

 diagrammatic. There should be a great many more of the large 

 black granules in the chambers, but, in order not to obscure the draw- 

 ing too much, comparatively few have been shown. The granules are 

 all perfectly globular, but vary somewhat in size, the majority being 

 large. In many places they are seen to be ejected into the atrial 

 lumen. 



Penial chamber (p1. v, fig. 2). — Inside the penial bulb the lower 

 part of the sperm-duct is enlarged, forming a penial chamber. This 

 chamber is lined by cubical epithelial cells, between which some ducts 

 from atrial glands seem to open. The lower part of the penial cham- 

 ber is lined by narrow glandular cells with very fine granulation and 

 with rather large oblong nuclei. The outermost of these cells are dif- 

 ferent from the rest, having longer and narrower nuclei. They also 

 stain a little deeper. 



Penial glands (p1. v, fig. 2). — The glands properly designated 

 penial glands, and confined to the interior of the penial bulb, are of 

 two kinds. The regular penial glands, collected in large bunches, 

 open as usual on the surface surrounding the pore. There are, besides 

 these glands, also a large number of single glandular cells opening 

 into the walls of the penial chamber. They can be clearly seen to 

 penetrate between the muscles of the wall. 



Nefhridia (p1. v, figs, i and 3). — The nephridia are unusually 

 interesting, not so much on account of their form, but because of 

 their similarity to the nephridia of the higher terrestrial Oligochfeta. 

 This similarity consists in a network of interlacing ducts, situated im- 

 mediately below the nephrostome. The network of ducts, consider- 

 ably finer than figured, soon collects into the outermost canal of the 

 nephridium, the lumen of which duct is quite narrow. Another 

 characteristic of the nephridium is the presence of ciliated ducts. The 

 exact location of these ducts it is not possible to determine at present, 



