ANATOMY OF TEHNIA MEDIOCANELLATA. 19 
the form of amassed granules,showing their functional activity 
by the comparative rapid imbibition of colouring matter ; 
and that the lower half of the segment anticipated the upper 
half. 
The female system preceded the male in all corresponding 
parts, the uterus and vagina, then the ovaries, subsequently 
the connection of the former with the latter through the 
ovarian tubes; equally the bulb of the penis was first ap- 
parent in the male system, then the seminal glands, ulti- 
mately the connecting channel—the seminal duct or vas 
deferens. Judging from the condition of the ova fecundation 
must have taken place at the 590th segment, and after this 
the female passages become a mere receptacle for the maturing 
germs which evidently ripen irregularly, as evinced by the 
commingling of advanced and progressing ova in the same 
gland, and equally as well in the passages as in the site of 
their production, 
Concerning the ova we may say that the vitelline particles 
in the earliest stage are spherical, oval, or irregularly com- 
pressed masses of protoplasm with a strongly defined nucleus, 
and average ;;/>5 Im. In size (fig. 17, a). Large fat-globules 
stud the protoplasm, and division of the nucleus ensues 
until the segmentation fills the thick double-outlined wall 
(6 to e). Separation cf the components takes place into two 
parts, a sharply defined, firm, yet elastic, spherical body, the 
former nucleus, the future egg; an irregular soft surround- 
ing granular mass (fig. 17, f). The spherical body gradually 
becomes more and more pronounced and increases in firm- 
ness, a double outlined wall is seen with radiating lines upon 
it and enclosing a globular body, the embryo; while the 
soft surrounding protoplasmic material assumes an irregular 
outline and wastes (gy, 2). The ovum darkens, the shell 
becomes rigid and the radiating lines more defined, the 
encircling soft mass disappears and the egg is matured (é). 
As such the average size is =}, 1In., but varying from =1, to 
«ta; Shape spherical, oval, or flattened on one side from 
compression, or half-moon form; colour dark brown; the 
shell is rigid but friable, with radiating lines made up of 
minute pits on its inside; within the shell is a membrane 
which loosely retains the embryo. This outer protection is 
remarkably indestructible ; alkalies have no effect on it ex- 
cept rendering its characters more clear, apparently from 
producing complete transparency of the surrounding albumi- 
uoid material; dilute acids (1 to 10) are innocuous ; tempo- 
rary immersion in stroug acids leaves the shell still intact, 
nitric acid colouring it yellow, sulphuric acid brown ; twenty- 
