338 MOORE. [Vol. XIII. 



hand, the stalk cell on the other. Like the former it is 

 thickened dorsally where the nucleus is situated, and is thinner 

 ventrally (Figs. lo, lo*^); like the latter it is tubular, and bears 

 a longitudinal tract of cilia within its lumen. These cilia are 

 very long, and arise from the dorsal wall contiguous to the 

 nucleus. In B. illuminatus they all extend down the funnel 

 (Fig. 6), while in the other species some of the upper ones 

 pass outward through the nephrostome with the marginal cilia 

 (Figs. 8, 9, and lo). They beat with a rapid wave-like motion, 

 which here recurs much more frequently than in other parts of 

 the nephridial tubule. The marginal cilia have a rotary motion 

 which is very obvious at the nephrostome, and in the few favor- 

 rable views which I have had from right to left (Fig. 7). 



The funnel stalk is a simple narrow tubule (Figs. 5, 6), 

 exactly like the simple tubules of the plexus region, except that 

 it is narrower and the course of its lumen sometimes more 

 irregular, or rarely even spirally wound within the tubule 

 (Figs. I, 5, and 6). 



4. TJie Plexus Region. 



With regard to this region of the nephridium the accounts 

 of Branchiobdella are very unsatisfactory. Odier (29) has called 

 the massive portions of the nephridia the red glands. Henle 

 (21) designates the region as the yellow granular body, and 

 notes its glandular nature, and its enclosure of a tissue of 

 twisted tubules. Keferstein (24) describes it as a yellow 

 glandular mass containing a snarled group of tubules enclosed 

 by granular pigmented cells. Dorner (14), more fully but 

 somewhat uncertainly states that "the canal into which the 

 funnel passes is immediately thrown into many closely lying 

 folds united into a thick skein and covered by a yellow-brown 

 pigment. This becomes more massive with the growth of the 

 animal, and in the adult is visible to the naked eye as a brown 

 spot; in young examples the separate windings are more dis- 

 tinctly perceived. . . . That the tubes present in the skein are 

 parts of a single canal bending closely against and around itself 

 cannot certainly be concluded from observation, but a consider- 

 ation of the familiar segmental organ of Lumbricus renders 



