iME. P. H. GOSSE ON THE DKECIOHS CHAEACTEE OE THE EOTIEEEA. '315 
10. After about five hours from extrusion the motions of the enclosed embryo become 
very vigorous: the folds of the body are continually changing their places, and the 'work- 
ing of the cilia is strong and rapid. Presently the regularly elliptical form of the egg 
undergoes a shght alteration, becoming more elongated, then slightly constricted in the 
middle, apparently by the pushing outwards of the two extremities of the body, and by 
the inflation of the fore-parts. At this moment the anterior half of the egg-shell is 
pushed off ; the cilia are instantly seen expanded and rotating for a second or two ; the 
httle new-born Bracliionus (see fig. 2) sits in the hinder half of the shell, as in a nest, 
and then ghdes away. 
11. The infant Brachionus s-wims rather feebly at first; but, acquiring ■vigour as it 
goes, presently darts along with amazing s-wiftness, so that the eye can scarcely follow 
it. WTien several of the young were hatched, they whirled and shot round and round 
the hve-box in which they were enclosed, in the most headlong manner, and were every 
instant coming into contact 'udth the parent, when, almost invariably, the course of the 
httle creatm’e would be arrested, and it would play around the body of the mother, or 
grasp 'uith its pincer-hke toes her chia. As 1 have already said, I had at that time no 
notion of these being males, ha\dng seen no offspring but these produced from this 
species. I had, however, seen the bu’th of several young of Brachionus urceolaris, which 
were exactly like the parent, whereas these were very dissimilar ; a chcumstance which 
excited my cuiiosity, as did also the fact that both eggs and young were notably smaller 
than those of B. urceolaris^ in proportion to the adult. The actual dimensions of the 
eggs in question were s^th of an inch in the longer diameter ; of the new-born male, 
g-^th ; of the parent, j^th, exclusive of the foot. 
12. I shall not here describe the structure of the male, because I shall presently have 
occasion to recur to the species again, in recording observations made -with the advan- 
tage of more experience. 
13. In April 1850 I flrst saw eggs of two different dimensions, attached to the same 
species. This was Brachionus rubens^ several specimens of which carried each seven or 
eight small eggs (fig. 3), measming 3 ^th of an inch in length, while others carried few 
eggs (two or three at most), nearly t-wice as large, 'viz. of an inch in length. One 
of the latter, under slight pressure, freed prematurely a young one, enveloped in a spined 
lorica, agreeing in all respects with the parent. I then crushed several of the smaller 
eggs. From such as were nearly mature, numbers of spermatozoa were expressed : these 
had a round body, and a short tail which was ■vibrated in a serpentine manner. They 
measured about sxoofh of an inch in the diameter of the body, and the length of the 
tail was about the same (fig. 4). These were sufficiently numerous to make it appear as 
if the eggs had been enthely filled with them. The less mature eggs yielded sperma- 
tozoa also, but ■without motion, with the tail undeveloped, adhering together, and some- 
what resembling blood-disks. 
14. Others of the smaller eggs produced the young by natural maturation. These 
were quite diverse from the parent, ha'ving no perceptible lorica, nor any spines; no 
2 T 2 
