64 COCCOPHYCEE. 
Popular Science Review, vol. v. p. 187. A. W. Wills in 
Midland Naturalist, Sept.-Oct., 1880. A. Bennett in Popular 
Sci. Rev. 1878, p. 225. 
Spherosira volvox, Ehr. Infus. (male). Pritch. Infus. p. 
526. Williamson in Popular Sci. Review, vol. ix. p. 225. 
Volvoz stellatus, Ehr. Infus. (oospore). 
In clear pools, ponds, &c. 
The relationship of Spherosira voluox to Volrox globatur has not been 
satisfactorily determined (see Williamson), although there remains no 
doubt of the existence of relationship. Some regard it as the male 
form, but Professor Williamson considers it w peculiar condition of 
Volvox. 
For details of a successful experiment in keeping Volvow during the 
winter see N. E. Brown in Gardener’s Chronicle (1879 p. 599) and 
‘‘ Ponds and Ditches,” by M. C. Cooke, p. 63. 
Plate XXII. figs. 1-3. Volvow globator, after A. W. Wills; 4-5, after 
Cohn. Explanation given above. 
Plate XXIII. figs. 1-5. After A. W. Wills; 6, ideal section after 
Williamson ; 7, after Wills—also fully described above; 8-9, X 300 
after Stein; 10, complete antheridium; 11, stellate resting spore or 
oosphere X 400 (Volvow steliatus) ; 12, spermatozoids x 600. 
Plate XXIV. Male plants of Volvox, known as Spherosira volvor, 
after Williamson, ig. 1, coonobium; 2, protoplasmic mass from the 
ccenobium, containing granules; 3, mass divided in two; 4, the same 
divided into four; 5, the same divided into sixteen; 6, further division 
into thirty-two, provided with movable cilia; 7, discoid family revolving 
within its mother-cell. 
Volvox minor. Stein Infus. p. 47. 
Ceenobia and the number of cells smaller; the number of 
daughter-ccenobia evolved without sexuality within the mother, 
1-9; fructification sexual, monecious; many male cells 
changing into bundles of spermatozoa; 5-10 f cells in 
the same ccenobium, after fecundation, evolved 
oospores, surrounded by a smooth epispore (—Volvox dMgeus, 
Ehbr.). 
te Variable, but smaller than the preceding. . \ 
Rabh. Alg. Eur. iii. 98. Stein Infus, t. - 
Volvox globator, of authors, in part. 
Volvox aureus, Ehrb. Inf. 71, t. 4, f. 2 (oospore). 
In similar places to the preceding. 
Plate XXV. Volvo minor X 400 after Stein. ig. 1, portion of 
ccenobium with two young daughter families ; 2, ceenobinm with two 
young daughter families enclosed in mother-cell ; 3, conobium with five 
young fertile cells; 4, ccenobium with six young fertile cells; 5, a fer- 
tile cell enclosing numerous vacuoles indicating the commencement of 
subdivision ; 6, isolated daughter-family still enclosed in the mother- 
cell; 7, encysted cell—the Volvow aureus of Ehrenberg ; 8, isolated 
ordinary individual enclosed in a flask-shaped cell. 
