484 MONTGOMERY. [Vol. XV. 



surface of the latter, these ducts transversing a large number of 

 body segments (in certain of the enchytraeid Oligochaeta there 

 have been described subcutical gland cells whose ducts pass 

 through a number of segments, but I believe that they are not 

 of the same relative length as those of Piscicold). Each cell has 

 its own duct, the latter being morphologically merely a process 

 of the cell (Figs. 178, 181, 202) ; and as these individual ducts 

 run in bundles parallel to one another, on their way to the sur- 

 face of the body, they become closely apposed to one another, 

 but there are apparently no open communications between the 

 several ducts, nor do they unite to form larger, compound ducts. 

 The ducts of those gland cells which are situated behind the 

 sexual pore necessarily have an anterior direction, while those 

 which are situated near to the head end of the animal send their 

 ducts posteriorly. The duct departs from the cell more or less 

 at right angles from its distal end, i.e., that end which is usually 

 directed towards the central axis of the worm. Since the greater 

 number of these cells become filled with secretion only when the 

 worm is sexually mature, and since they all open on the surface 

 of the body near the sexual pore, they have probably the same 

 function as the clitellar glands of the Oligochaeta; after these 

 observations had been completed I found that Bourne ('84) had 

 described such gland cells in Po7itobdella as " clitellar glands," 

 but he made no observations on their finer structure. 



In studying the cycle of the structural changes of these 

 cells two main morphological periods may be distinguished : 

 (i) thQ prophasis, from the immature cell to the cell filled with 

 secretion ; and (2) the metaphasis, from the time when the 

 cell begins to discharge its secretion until it becomes re-formed 

 into a functionally immature cell again. I have no means of 

 determining whether a given cell becomes filled with secretion 

 only once a year (as, e.g., at the period of sexual maturity) or 

 whether it may secrete several times in succession during the 

 sexual period. At any rate, all appearances lead me to con- 

 clude that it secretes periodically, most probably once during 

 each period of sexual maturity. I have found no evidences that 

 it secretes only once and then dies to become absorbed by 

 the other tissues of the body ; in other words, there were no 



