VOLVOCINEE. 63 
develop into plates or discs of cells, not into spheres, and ultimately 
resolve themselves into bundles of naked elongated cells, in which the 
chlorophyll is transformed into a reddish pigment, each with along 
colourless beak, with a red ‘eye-spot’ and twocilia. (Plate 22, Fig. 
5a, a?.) About the same time that the oosphere is mature these 
antheridia begin to move from the combined action of their cilia (Plate 
23, Fig. 10), and then break up into separate antherozoids, which finally 
become free, and move rapidly within the cavity of the sphere. (Plate 
23, Fig. 5a5.) Assembling round the oospheres, they penetrate the 
envelopes of the latter (Plate 22, Fig. 4), coalesce with their contents, 
and the oosphere, thus fertilised, becomes an ovspore, which soon develops 
a cell-wall covered with conical stellate projections, and a second smooth 
internal membrane. (Plate 23, Fig. 11.) The chlorophyll now gradually 
disappears, and is replaced by an orange red pigment. In this condition 
the oospore constitutes the Volvow stellatus of Ehrenberg. It is liberated 
by the decay of the parent-cell, and sinks to the bottom of the water 
to hibernate. The subsequent history of these bodies has been traced 
by Cienkowski, and more recently by Henneguay (“Journal de 
Micrographie,” Vol. II., p. 485, Bull. Soc. Philomath, Paris, July, 1878). 
“Cohn believed that they must be dried up before germination was 
possible. Henneguay has now observed that this is not so. In spring 
the outer case of the spore (exospore) is ruptured, and the swollen con- 
tents (endospore) project through the opening. The contents then 
divide gradually into two, four, eight, sixteen, or more small cells, which 
become bright green, each meanwhile acquiring two vibratile cilia while 
still contained within the inner membrane of the spore. The cells, at 
first in close apposition, separate further from one another by interposi- 
tion of gelatinous hyaline matter, the outer membrane disappears, the 
cilia become active, and the young Volvox, already containing some 
elements larger than the others, and destined, in due course, to produce 
danghter-spheres, moves freely through the water. ‘The spores of 
Volvox, therefore, germinate in water, and each of them produces a 
single colony by a process of segmentation identical witb that which 
gives rise to 4 danghter-colony at the expense of a cell of the mother- 
colony.’ 
“The sequence of asexual generations is repeated for many months, 
and in the following autumn the alternation of generations is again 
completed by the intervention of the processes just described.” 
Volvox globator. Linn. Syst. Ed. x. 
Larger ccenobia, with very numerous cells (12,000), always 
with daughter-ccenobia enclosed within the mother, evolved 
without sexuality ; fructification diwciousy,the male ccenobia 
nourishing numerous red fascicles of spermatozoa; the female 
ceenobia originating 20-40 sexual cells, which after fecundation 
are resolved into as many red globose oospores, surrounded by a 
hyaline stellate epispore (—Volvow stellatus, Ehr.). 
Size. Ccenobium as much as 1 mm. diam. 
Ehrb. Infus. 68, t. 4.- Dujardin Zoophy. 812, iii. f. 25. Stein 
Infus. p. 46. Rabh. Alg. Eur. iii. 97. Pritchard Infus, 526, 
t. 20, f. 32-47. Busk. Trans. Micr. Soc. 1853, p. 31. Wil- 
liamson Trans. Micr. Soc. 1853, p.45. Currey Ann. Nat. Hist. 
1859, p. 5. Dr. J. B. Hicks in Micro. Journ. 1861, p. 28] ; in 
