ox THE FOE3IATIOX OF THE EGG IX THE AXXELOSA. 
GU 
the maximum size, become merely vitelligenous bodies, and not truePurkinjean vesicles, 
I could not satisfactorily ascertain. If even, however, this is the case, the yelk-forming 
nuclei do not themselves enter the follicle. 
It results from the above description that the ovarian capsules consist of a simple mem- 
brane, and are not bounded, as in insects and Myriapods, by any inner layer of epithelial 
cells. The smallest Purkinjean vesicles observed were about of an inch in 
diameter, and had a single solid-looking macula. At this period the Purkinjean vesicle 
and the yelk are quite clear and transparent ; nor are they darkened by the action of 
dilute acetic acid, though the former is, as usual, destroyed by it. 
When, however, the egg-follicle is about of an inch in diameter, the yelk begins 
to become granular, and in consequence darker in colour. The granules are at first 
quite small, but they rapidly increase in number pand when the egg is ^f-^ths of an inch 
in size it has become quite opake. 
During all this period the Purkinjean vesicle remained unaltered, except in size. The 
macula also enlarges, and becomes vacuolated ; but I never saw it break up, nor was I 
able to determine its ultimate destination. In an egg ^uo^hs of an inch in length, the 
Purkinjean vesicle was as before, the macula single and vacuolated. 
No trace of either Purkinjean vesicle or macula could I ever detect in the full-grown 
egg from the matrix. These eggs were of an elliptic shape, of an inch in 
length, by about -juu^ths in breadth. The yelk consisted, 1st, of minute, round, 
greenish globules about yo o 6 o th of an inch in diameter ; 2ndly, of the usual trans- 
parent, somewhat viscid substance ; Srdly, of irregularly-shaped, solid-looking yelk- 
masses, about of iiich in diameter, and each generally appearing to contain a 
rounded globule in its interior. 
The chorion is a single, simple, transparent, structureless membrane. 
The other species of Phalangidae which I liave dissected are Vhalangium cormitum, 
Leiohunus rotundas, and Opilio agrestls, all of which, in the arrangement of their gene- 
rative organs, agreed in all essential particulars with the preceding species. 
In Leiohunus rotundus the ovarian nuclei were as distinct as in Nemastoma hiniacu- 
latum, but rather smaller ; in P. cornutuni they are more delicate, and the contents are 
less granular. The formation of the egg, of the Purkinjean vesicle, and of the macula 
proceed almost exactly as in the preceding species, and need not therefore be again 
detailed. In Z. rotundus, however, the macula has not the appearance of a vesicle, but 
rather of a cloud of small granules compacted together. 
In some cases the ovary presents a rather unusual appearance, from the fact that the 
stalks of the ovarian follicles are not circular, but elliptic ; this peculiarity struck me 
more particularly in Leiohunus. 
The eggs of I\ cornutuni begin to darken when they are about of an inch in 
diameter ; and the yelk then consists of very fine particles, not more than ' aoouu f^^ of 
inch in diameter. 
fri P . cornutum i\iQ. egg had become cpite opake when it was about -^l^oths of an 
MDCCCLXI. 4 0 
