Volvox and Associated Algae from Kimberley. 493 



Daughter colonies most often eight, arranged symmetrically in pairs, 

 two pairs nearly equatorial, two nearer the posterior pole. The pair 

 most nearly equatorial develops first, other pairs develop successively 

 in order of their position, the most posterior developing last. Anterior 

 pairs may have inverted and may contain developing gonidia before 

 cell division in the posterior pair is complete. In some of the young 

 coenobia the four central daughters were in early stages of division, 

 while two pairs of undivided gonidia still in the stage of enlargement 

 and 35 /JL and 28 p, respectively in diameter occupied positions near 

 the posterior end. Sometimes fewer, rarely more than eight, daughters 

 develop ; colonies with six, five or even fewer embryos were observed, 

 while in one case there were nine, an extra one having developed near 

 the equatorial plane. If an odd number develops, an abortive 

 gonidium representing the missing member of the pair is usually, but 

 not invariably, traceable. 



The protoplasts of the somatic cells are rounded, without proto- 

 plasmic connections. In the developing embryo, however, inter- 

 cellular protoplasmic strands are present until inversion is achieved, 

 and occasionally one here and there survives and can be seen in the 

 unborn embryo. 



Coen. asex. . . 366-926 /* x 387-1077 p 



Embryo, inverting . . 75 x 90 ^ 



Embryo, mature . . . 366 x 451 yu 



Gonidium, mature . . . 28-44 /z 



Gonidium in inverting embryo. 9-16 p, 



Somatic cell .... 16-20//, 



Somatic protoplast . . . 5-7 p. 



No. of cells .... 3000-7000 



Found in Pool II only ; rare, associated with V. Rousseletii. 



This species was found in Pool II late in the season, after the last 

 rains. It was present in very small quantities mixed with numerous 

 very large, vigorous, but young asexual colonies of V. Rousseletii ; 

 not a single sexual colony of either species could .be found, although 

 the pool was visited several times until it was completely dry. It is 

 to be hoped that next season it will be possible to keep this pool 

 under observation for a longer period and that sexual material will 

 be obtained so that the description of the species may be amplified, 

 since West did not obtain satisfactory male material, and even Shaw, 

 in his extended description (1923, p. 197), does not describe the male 

 reproductive organs fully, and differs from West in some details. 



