STUDIES ON EARTHWORMS. 279 
in Microcheta, but it is enclosed only in the thin-walled 
seminal reservoirs, whilst in the latter it is enclosed in a 
special cecum of the seminal reservoir, which possesses a 
strong wall. 
c. The Sperm Ducts and Ciliated Rosettes.—Each of 
the four ciliated rosettes (c. 7.) lies, as stated above, in a sac ; 
two in somite 1x, twoinsomite x. From each rosette there leads 
a narrow sperm duct (sp. d.), which immediately passes through 
the septum, and then backwards and outwards till it reaches 
the next septum, beyond which it is continued directly back- 
wards, closely adherent to the body wall, and just within the 
line of the nephridiopores, to the commencement of somite 
xiv. Here it joins the other duct of the same side, and the two 
pass on as one duct to their external pore in the somite xix. The 
separation from one another of the two ducts of one side for so 
many somites is perhaps noteworthy. ‘There are no accessory 
copulatory organs. 
B. Female Organs.—(a) Ovary.—Lying on the anterior 
septum of somite xi11, close beside the intestine, on each side, 
is a dark hemispherical mass of celis (O.) (figs. 2, 4), appear- 
ing, even to the naked eye, to be made of a number of lobules ; 
it is fairly large, being about one eighth inch along its base. 
These are the ovaries, and microscopic study shows that each is 
made up of a number of lobules, which contain masses of ova 
(P1. XVI, fig. 14). I could see no gradation in size amongst 
the ova of any given lobe, corresponding to a difference in age of 
the ova, such as we find in the ovary of Lumbricus. Hach 
ovum, consisting of a granular protoplasm with well-marked 
nucleus and nucleolus, is surrounded by ccelomic epithelial cells. 
Thus the shape of the ovary differs a great deal from what 
obtains in Lumbricus, and resembles the ovary in Plutellus and 
Pontodrilus ; being as it were made up of a number of Lum- 
bricus’ ovaries, each without the characteristic “tail”? It may 
be that here the ova were not far enough advanced, that they 
were too young, to show this “ tail;” for in young ovaries of 
Lumbricus the tail is not very pronounced; in the case of 
Microcheeta we should then get a tail to each lobule. 
