184 M. Sars on the Development of the Annelides. 
gation of this Annelide: in some individuals, the body, which at 
other times is of a light brownish gray or whitish gray and 
shining with a blue reflection, is observed to have assumed a pale 
rose-colour. This arises from a numberless quantity of eggs 
which fill the common cavity of the body, with the exception of 
about the first anterior fourth and the feet, and appear every- 
where through the skm. When the skin is cut open, the eggs 
ave found to hang together in great masses by means of a con- 
necting tenacious mucus. They are spherical, the yolk finely gra- 
nular and opake, closely surrounded by the transparent chorion. 
When the egg is somewhat compressed (Plate IV. fig. 13), it ex- 
hibits the large Purkinje’s vesicle without any perceptible trace 
of Wagner’s spot. In other individuals the eggs have frequently 
been secreted at about the same time. ‘They occur on the top of 
the back of the mother, beneath the branchiz or so-called dorsal 
scales, in immense numbers, connected with one another by a 
tenacious mucus. 
The heaps of eggs cover the whole of the hinder half of the 
back, but more anteriorly only the sides above the base of the 
feet : no eggs are met with on the seventh to the eighth front rigs 
of the body. It seemed to me as if the eggs passed through a very 
small aperture just above the feet, as Rathke found to be the case 
in Nereis pulsatoria. They are all of the same size in the same 
individual (viz. about 1th of a millimeter), and mostly equally 
developed, and therefore all of one and the same brood. ‘Their 
colour is still very pale rosy red, or almost reddish white. Here, 
protected beneath the branchie, the eggs remain until the young 
creep out. In the meantime the yolk, between which and the 
chorion is a small space filled with hmpid albumen, undergoes 
the usual process of division or furcation. Thus I once observed 
that the yolk had the appearance of a blackberry (fig. 14), its sur- 
face being covered with granules of different sizes, as was proved 
on submitting them to compression (fig. 15); each contained a 
bright roundish spot with a distinct outlme like a nucleus, and 
were therefore evidently cells. On the following day, the 4th of 
March, the surface of the yolk had already become more finely 
granular, and approached again nearer to an even surface. 
The ova subsequently become slightly oval, and the yolk or 
foetus into which the entire yolk is converted, without any part 
whatever separating, is smooth, grayish white, and is more or 
less narrowly surrounded or inclosed by chorion (fig. 16,17). A 
peculiar kind of motion was now perceptible on the separated 
ova under the microscope, the ova turnmg round and round. 
This was effected by the very short fringe, consisting of mimute 
mucous filaments (fig. 16,17 a), which is attached to the one ex- 
tremity of the ovum, and probably covering the entire egg in the 
