Miscellaneous. 75 
being to recall the fact of its inaccuracy, or inserting it between 
inverted commas to show my disbelief in it, 
Mr. Distant is too old a friend not to besure that I should at once 
prefer the name proved to be of earlier date whether it displaced 
my own or not: to retain one’s own name for a species when 
priority has been proved for that of another author, is a childish 
form of egotism of which, as he well knows, I was never guilty. 
On the Fecundation and Development of Hermella alveolata, M.-£. 
By Dr. R. Horst. 
In his ‘Mémoire sur l’embryogénie des Annélides” (Ann. Sci. 
Nat. sér. 3, Zool. tome x. p. 153), Quatrefages described the various 
stages in the evolution of Hermella alveolata ; and two years after- 
wards (ibid. tome xili. p. 126) he published his researches upon the 
fecundation and conditions of development of this annelid. Tho 
author has had the opportunity of making a fresh investigation into 
the subject at Prof. Giard’s laboratory at Wimereux, near Boulogne. 
He finds that the ova of Hermeila alveolata have a strongly era- 
nular vitellus, a large germinal vesicle, and a very distinct germinal 
spot. At first the vitellus is in contact with the vitelline membrane ; 
but as soon as the spermatozoids come into contact with the ovum, the 
vitellus separates a little from the wall of the latter, and at the same 
time a concentration of the granules of the deutoplasm takes place, 
so that a transparent layer of protoplasm forms at the periphery 
(the enveloping layer of Fol*). It is very probable that the sepa- 
ration between the membrane and the vitellus is not due solely to 
the contraction of the latter, but also to the penetration of water by 
osmosis, as was supposed by Quatrefages, and as Calberla + has 
shown to be the case in the ova of Petromyzon. This peripheral 
space does not entirely separate the vitellus from the vitelline mem- 
brane, the relation being maintained by numerous scarcely visible 
filaments surrounding the vitellus like a halo. Calberla observed 
the same phenomenon in the ova of Petromyzon t. 
When a spermatozoid is occupied in penetrating the vitelline 
membrane, a broader filament than the rest, like the pseudopodium of 
an Amceba, advances from the periphery of the vitellus to meet the 
spermatozoid, until the latter has perforated the vitelline membrane. 
In about twenty minutes the spermatozoid makes its way into this 
vitellic filament and becomes confounded with it; the process of 
the vitellus then gradually contracts; and in this way the spermato- 
zoid penetrates into the vitelline mass. 
Spermatozoids do not penetrate into all the filaments, one of 
which will often disappear while another originates at the peri- 
phery of the vitellus. The author believes, however, that more 
spermatozoids than one penetrate the ovum. About an hour after 
* ‘Recherches sur la fécondation,’ &c. 
+ Zeitschr. fiir wiss. Zool. vol. xxx. p. 437. 
$ Loe. cd. p. 408, pl. xxxvii. figs. 7, 8, pl. xxxix. figs, A, B. 
