46 EISEN 



fact that the brain-cells are carried out on the powerful retractor mus- 

 cles connecting the brain with the body-wall. 



Spermat/ieccB are strong and rather contracted. They are of large 

 size, even for a worm of the unusual size of our present species. 

 i Sperjn-ducts. — The funnels long and thin, and in the specimen 

 turned backward. The ducts extend backward some six or seven 

 somites, but on account of the length of the funnels are not over three 

 times as long as the former. The most interesting part of the organ 

 is, of course, the atrial part with its glands. There is a long and 

 narrow atrium outside the bulb and a wider penial chamber within. 

 The openings of the atrial glands are close to the penial bulb and 

 close to each other. As has already been stated, the ducts of the indi- 

 vidual cells, after entering the atrium, penetrate its inner layer all 

 along down to the penial pore. The shape of the glands is also some- 

 what characteristic, being long and even and much less pear-shaped 

 than those of the other species which have so far come under my ob- 

 servation. 



Sperm-sacs. — The two usual sperm-sacs are present. They begin 

 as far forward as somite VII, where they appear to spring from the 

 septum VI/VII. They gradually increase in size posteriorly, except 

 in the somites of the clitellum, where they are thin, even and tubular. 

 The walls of the sperm-sacs are thick, a cross-section resembling a 

 cross-section of a spermatheca. 



Lymphocytes (p1. vii, figs. 3-6). — There are in reality two kinds 

 of lymphocytes, one with cyanophil and one with eosinophil granula- 

 tion. The cells may also be void of any granules, in which case one 

 kind cannot be distinguished from the other. The cells are globular, 

 rounded and mulberry-shaped, as regards outline. The cytoplasm is 

 coarsely reticulate, the nucleus small. In cells with cyanophil granules, 

 the latter are of even size and uniform shape, rather squarish and with 

 blunt ends. There are from six to ten or more of these granules in 

 each cell. The granules are quite separate one from the other. In 

 the other kind of cell the granules are of all sizes, some very minute, 

 others several times larger than the cyanophil granules. Of these 

 eosinophil granules there are many more in each cell, sometimes as 

 many as twenty or thirty. They are frequently thrown out in the 

 ccelom, and are here found in all sizes, entirely free from the lympho- 

 cytes themselves. The eosinophils are by far the smallest of these two 

 kinds of lymphocytes ; the difference in size is however not great. As 

 will be seen, even the lymphocytes resemble those of M. harrtjnani to 

 such an extent that a close relationship exists between the two species. 



