84 ME. LUBBOCK’S ACCOUNT OF THE TWO JMETHODS OF EEPEODUCTIOK 
greatly in number, and formed finally a large, firm-looking, dark homogeneous mass, the 
ephippial egg. In its later stages it may easily be distinguished from the matter of the 
agamic eggs, by the darker colour, more regular outline, and absence of large oil-globules. 
There are never more than two ephippial eggs in Daphnia, one being formed in each 
ovary. Prof. Huxley appears to have not very clearly apprehended the relation of these 
two ova to one another, and to the ephippium, for he compares them to two masses 
formed in the ephippial egg of Lacinularia* , whereas they are two distinct eggs, and the 
ephippium of Daplinia is not an egg-shell hke the external shell of the winter eggs of 
Rotifers, but a portion of the carapace, and therefore analogous to the skin of the female 
Coccus, which acts as a protection to the eggs beneath it. During the last hours before 
its deposition in the ephippium, the ephippial egg appears to occupy the whole of the 
ovary, or rather the latter cannot be distinguished ; and if at this time the ephippial egg 
is removed from the body and compressed, there will be seen an immense number of 
minute cells, some *00083, but by far the greater number about *0001 in diameter, and 
also some of the usual ovarian cells containing the nuclei, which I call germinal vesicles. 
These latter, however, do not, I beheve, belong to the egg itself: the chorion is at this 
period so delicate, that I have never been able completely to isolate the egg from the 
other contents of the ovary ; but I examined it several times as soon as it was laid, and 
found it to contain only the above-mentioned minute cells. The mother-cells, or those 
containing the germinal vesicles, could then be clearly seen in the ovary, and I beheve, 
therefore, that the above-mentioned disappearance of the ovary is only apparent. 
The most accurate account given of the ephippium is that by Steauss, who saysf : — 
“ a certaine epoque de I’annee, notamment vers les mois de JuiUet et d’Aout, les valves 
de la femeUe prennent, apres la nuce, de I’opacite dans leur partie superiem’e, chacune dans 
une etendue a peu pres rectangulaire, s’etendant depuis les envfrons du premier segment 
jusqu’au sixieme, et descendant jusqu’au dessous de la region des ovafres. Cette pai*tie 
opaque est d’abord de couleur un peu blanchatre : mais devenant bientot plus foncee, 
elle finit par etre d’un gris noiratre assez obscur. Sur chacune on apercoit deux ampoules 
ovulafres, transparentes, placees Tune au devant de I’autre, et formant avec celles du cote 
oppose deux petites capsules ovales, s’ouvrant comme une coquille bivalve. ISIullee a 
nomme ces pieces opaques un ephippium, sans dhe toutefois ce qu’il en pensait: et 
comme elles ont en efiet, \'u leur situation sur le dos de I’animal, quelque ressemblance 
avec une selle, j’ai cru devou* conserver cette denomination, pour ne pas introduh*e de 
nouveaux termes inutiles. Get ephippium se partage comme les valves, dont il fait 
partie, en deux moities laterales, reunies par suture le long de leiu* bord superieur. 
Dans son interieur on en trouve un autre semblable, mais plus petit, a bords fibres, et 
dont les deux moities jouent en charniere une sur I’autre.” 
This account is very accurate : Steauss expressly states that the ephippium is a part 
of the carapace, a fact which has been miscomprehended by subsequent ■v^uiters. Thus, 
Dr. Baied says (p. 85) that a green matter passes from the ovaries into the receptacle, 
* Loc. cit. p. 14, t Ann. de Musee, 1819, vol. v. p. 415. 
