626 



occasionally obscured by a peculiar modification of the nephridium in 

 which the posterior half of the postseptal part is bent ventrad and 

 cephalad, and is in such close relation to the ventral side of the an- 

 terior half that the origin seems to be near the septum. 



Spcrniidiical Funnel. — The spermiducal funnel (PI. CI, Fig. 26) 

 is very large, and the two funnels occupy the greater part of the 

 coelom in XL They are barrel-shaped and about twice as long as their 

 diameter. Each has a distinct reflected collar set off from the body 

 of the funnel by a constriction. The diameter of the collar is less 

 than the maximum diameter of the funnel. The sperm duct is long, 

 slendeH", and confined to XII. 



Pcnial Bulb. — The structure of the penial bulb (PI. CI, Fig. 27) 

 so closely resembles that already described for F. firm a that it seems 

 unnecessary to give a detailed description. The shape, relative size, 

 musculature, and relation to the body wall are all about the same as 

 in that species. Similarly, also, the body of the bulb is composed of 

 two distinct sets of cells, viz., the inner bulb cells, which immediately 

 surround the penial lumen, and the peripheral bulb cells, which com- 

 prise the greater part of the mass of the organ. The relation of the 

 bulb to the sperm duct is also similar to that described for F. Urma. 



Spcrmathcccc. — Each spermatheca (PI. CI, Fig. 28) has a dis- 

 tinctly differentiated duct and ampulla, the latter bearing diverticula. 

 The duct is slender and about three times as long as the ampulla. It 

 unites with the ectal end of the latter at the middle of the ring of 

 diverticula and extends, with few curves, to the ectal opening, which 

 is laterad and near IV/V. A few inconspicuous gland cells are pres- 

 ent about the ectal opening. The ampulla is barrel-shaped and thick- 

 walled. It bears a ring of about nine similar lobular diverticula at 

 the ectal end. The walls' of the diverticula are comparatively thin, 

 and the lumina are in direct communication with the lumen of the 

 ampulla. The spemiathecse communicate independently with the 

 digestive tract on its dorsal side in the posterior part of V. The 

 spermathece are quite large and occupy a considerable part of the 

 space in V. 



The Function of the Chyhis Cells in Fridericia 



The homologies and functions of these peculiar cells are, indeed, 

 quite problematical. The intimate connection of the cells with the 

 digestive tract and their close contact with the blood vascular system 

 indicate that they have an important role in some metabolic process. 

 Michaelsen ('86, p. 296) has maintained that they are organs of ab- 

 sorption. Eisen ('05, p. 107) also favored this interpretation, and at- 



