158 



send long extensions to the penial lumen. The second group of cells 

 occupies the ventral part of the bulb, and opens on to the surface of 

 the penial invagination. In nearly all of the preparations studied in 

 this connection it was not difficult to determine the line of separation 

 between these two groups of cells owing to the fact that they tend 

 to separate and produce a distinct split in the bulb at that place. 



All of the preparations examined, showed a few nuclei scattered 

 among the extensions of the dorsal cells at a position about half-way 

 between the periphery and the penial lumen. This recalls the fact that 

 in F. Urma, F. agilis, F. agricola, and in other species, there is a. group 

 of cells between the penial lumen and the peripheral dorsal cells which 

 is conspicuous in sections because of the arrangement of the numerous 

 similar nuclei in a definite row. Critical examination of this bulb has 

 failed to reveal a third definite group of cells in this organ. High 

 magnification shows that the scattering nuclei represent only occasional 

 cells interpolated between the extensions of the other cells. It is possi- 

 ble that the structure of this bulb represents a transition between the 

 type represented by F. firiiia and that represented by F. tencra. 



Spermathecce. — A rather surprising variation exists in these organs 

 in the different specimens. In order to be sure of sexual maturity 

 each spermatheca was examined carefully for spermatozoa, their pres- 

 ence being taken as evidence that the specimen was sexually mature. 

 The number of diverticula (PI. X, Fig. 28) varies from; about 7 to 

 II. They are of unequal size on the same spermatheca, and their 

 number may vary in members of the same pair. They are more or 

 less spherical, and the cavity of each has a wide communication with 

 the lumen of the ampulla. In some cases the diverticula are quite 

 distinct ; in others they are so obscure that at first sight there seems 

 to be none, but closer examination shows that they are uniformly 

 present. The ampulla is pear-shaped and connected with the digestive 

 tract. There is considerable variation in the position of this connec- 

 tion. In somle specimens it is near the mid-dorsal line and the ental 

 ends of the two ampullae lie so closely together that only very careful 

 examination of sections reveals the fact that they enter separately. 

 In other specimens the ampullse unite with the digestive tract laterally, 

 one exactly opposite the other. Furthermore, there is some variation 

 in the way in which they approach the digestive tract. They may ap- 

 proach similarly, or the ampulla on one side may curve dorsad and 

 unite with the digestive tract near the mid-dorsal line, while the other 

 extends directly to the mid-lateral surface and unites at that point. The 

 spermathecal duct is straight and its ectal opening is devoid of glands. 



