562 
PROFESSOR, ALLMAN ON THE STRUCTURE 
from within. By the continued contraction of the gonophore-walls the plasmodium is 
at last entirely expelled, completely enveloped, however, in a transparent structureless 
membrane. This is apparently the membrane which at a very early stage had shown 
itself lining the gonogenetic chamber ; it is at first of great tenuity, hut it soon acquires 
considerable consistence. The empty gonophore may now be seen retracted in the 
form of a shallow thick-walled cup with everted edges upon the summit of its short 
peduncle (fig. 14, e)*. 
The liberated plasmodium closely enveloped in its delicate structureless capsule is of 
a nearly spherical form, and now lies upon the retracted gonophore, where it is usually 
retained by the spadix plunged for a short distance into its mass (fig. 14 ,f). It does 
not, however, continue long in this position, for the function of the claspers is soon 
brought into play. These curious organs now stretch themselves out towards the 
liberated plasmodium ; and as soon as they reach it they attach themselves (f) by their 
sucker-like extremities to its capsule, and then by contracting pull it entirely away ( g ) 
from the remains of the gonophore. 
Sometimes the plasmodium will be seized by only one clasper ; very often, however, 
two or even three will fasten on it (Plate 55. fig. 2) ; and the plasmodium will sometimes 
be seen more or less distorted by the tension thus exerted on it at the same time in 
different directions. 
Leaving for a while the further history of the female elements, we may now trace the 
development of the male. The male gonophore resembles the female in all points 
except in being about half the size of the latter ; and I could detect no difference as to 
origin between the matter which in one case is to become differentiated into ova, and 
that which in the other is destined for the formation of spermatozoa. In every young 
gonophore I have examined, the first appearance of the matter in which sexual elements 
are afterwards to show themselves is within the gonogenetic chamber which has 
become excavated in the substance of the endoderm ; and it is only when the ovarian 
nuclei become differentiated in the one case, and the spermatic cells in the other, that 
we obtain any decided indication of the sex of the gonophore. 
As we have already seen, the primitive plasma which fills the gonogenetic chamber in 
the female presents after a time scattered nuclei-like bodies, which are to become the 
germinal vesicles of the ova. In the male, on the other hand, such nuclei never make their 
appearance, and the primitive protoplasm becomes changed into minute cell-like bodies, 
which entirely fill the chamber (Plate 57. fig. 15). These little bodies are the vesicles 
within which the spermatozoa originate ; but in what way the latter are produced from 
them I have not succeeded in discovering. After a time the vesicles have disappeared, 
and are replaced by mature spermatozoa, which now fill the cavity of the gonophore, 
and which may be liberated by rupture of the latter. When thus set free they are seen 
to consist of a very minute oval head, with a vibratile tail of extreme tenuity (fig. 16). 
* In a single instance a gonophore with two such plasmodia ready to escape from it came under my obser- 
Tation. 
