504 Philippine Journal of Science 191 » 



there is a small percentage of specimens of three other species 

 of Volvocaceae, including some of Volvox africanus West, a 

 species of similar dimensions. The mother coenobium of speci- 

 men 22 (Plate II, fig. 10) measures 230 by 270 p, and has somatic 

 protoplasts of about 5 ft diameter and cell diameters of about 

 9 /*, the number of cells being about 2,640. The asexual daughter 

 measures 95 by 105 ^ and contains seven gonidia. Of these 

 the smallest is 16 by 18 ^ and the largest, 43 by 45 fi. There 

 are six sexual daughters. Of these the smaller near one (in the 

 left side of the picture just above the middle) contains twenty- 

 seven reproductive cells, of which eight are small and medium- 

 sized, 11 to 12 jx, and nineteen are large, about 17 fu The larger 

 near daughter (in the lower side of the figure) contains about 

 twenty-nine reproductive cells of 15 to 18 it. The other daughter 

 with reproductive cells in plain view (the lower one on the left 

 side of the photograph) contains about thirty-one reproductive 

 cells of 15 and 18 fi, mostly of the larger size. The three other 

 sexual daughters have about the same number of reproductive 

 cells, and all of the sexual daughters are elongated and free 

 from reproductive cells in one end. A number of endophytic 

 algae are prominent in the walls of the mother coenobium. 



Several other examples of mother coenobia, containing mixed 

 broods of progeny differing in no significant particular from 

 the one just described were found on the slides of the lot under 

 consideration. 



A sexual coenobium with a smaller number of reproductive 

 cells occurs as a daughter in the mother coenobium shown in 

 Plate II, fig. 11. This specimen (No. 23) is on one slide (No. 

 1) of a lot prepared from the same material as the type slide, 

 but with the omission of the nigrosin stain. The mother coeno- 

 bium measured, when the micrograph was taken in June, 1919, 

 170 by 210 p. The somatic protoplasts were then about 5 ^ 

 in diameter and the average cell width about 7.1 ^. The esti- 

 mated number of cells is 2,420. The mother contains one goni- 

 dium, 52 by 53 /x, four asexual embryos, and one sexual embryo. 

 The most advanced asexual embryo is not much beyond the 

 bullet stage. This embryo is elongate, 57 by 75 ^ almost pointed 

 at the anterior end and blunt at the opposite end. It contains 

 eight gonidia of about 18 p diameter. Four of these are closely 

 grouped against the posterior wall of the coenobium, three lie 

 almost a gonidial cell diameter in advance of the posterior 

 quartet, and one is almost two diameters ahead of the quartet. 

 Beneath this embryo there lies one in the typical bullet stage, 



