270 THOS. H. MONTGOMERY, 



around it. It is of particular interest to note, that this hollow, thick- 

 walled, almond-shaped structure is completely closed on all sides, and 

 no pores nor radial openings of any kind are to be found in its wall. 

 Thus there is no open communication between the cavity of the term- 

 inal bulb, and the outside; but it is fully closed both against the 

 enveloping cells, as well as against the ductule which leads to the 

 main duct of the nephridium (Fig. 2). In the cavities of some of 

 these hollow almonds I have found, on fixed preparations, a finely 

 granulated, slightly-staining mass (Fig. 2 x)\ and in one case I no- 

 ticed a structure resembling a flame of cilia (Fig. 7 x). But while 

 examining living worms I never saw any evidences of such flames, 

 and although they might have eluded observation owing to the density 

 of the almond, nevertheless it would seem to be more probable that 

 such structures are absent here , since the mechanical action of a 

 ciliary flame within such a closed wall would be very problematical. 

 There occurs to my memory, indeed, no similar case in comparative 

 histology, unless perhaps in the form of small otocysts; but in the 

 latter case, the function of the cilia is rather sensory than purely 

 motory. The finely- granulated masses sometimes found within the 

 cavity of the bulb, I would explain as a coagulation of the fluid taken 

 up from the outside by the cells of the bulb. 



These terminal bulbs are very numerous, at least several hundreds 

 being present in a large individual, and they may be found in the 

 body-cavity from the extreme end of the head (below the cutis), to 

 the anus. Usually they are separated from one another, but occas- 

 ionally lie in such a way in contact, that their respective cuticular 

 almonds are fused together at one point (Fig. 6). 



Nephridial Ductule. These fine canals connect the terminal 

 bulbs with the main ducts, and there is a single one for each bulb 

 (Figs. 1, 7 d). They are canals of relatively great length, in pro- 

 portion to the other Nemerteans, with a small calibre and thin walls, 

 though these walls are thicker at the extremities of the ductule than 

 elsewhere. No nuclei at all are found along the ductule, and no cell 

 boundaries can be determined in its wall; accordingly, I am unable 

 to decide whether its wall is represented by an epithelium of cells, 

 such as Burgee ('92) has constated for numerous other forms, or 

 whether the cavity of the ductule is intracellular (as in the Turbel- 

 laria, and other Platyhelminths), or, finally, whether it represents 

 merely a continuation of the cytoplasm of the cells of the bulb ; the 

 last supposition seems to me, however, to be the most probable. The 



