210 The Philippine Journal of Science ™* 



REVISED DIAGNOSIS OF THE SPECIES 



In my first paper dealing with the genus Merrillosphaera 

 there is given a diagnosis of M. africana drawn entirely from 

 the accounts by West ('10 and '18) of the African material. 

 Since the forms here described all seem to belong to the same 

 species, the diagnosis of the species will be expanded to embrace 

 them. 



MERRILLOSPHAERA AFRICANA (West) Shaw. 



Volvox africanus West in Journ. Quekett Micr. Club II 11 (1910) 

 102-103, pi. 3, figs. 8-10; II 13 (1918) 425-428, pi. 29, figs. 4-6. 



Coenobia ovoid to ellipsoidal ; ranging from 295 by 345 to 500 

 by 600 {i. Number of somatic cells between 3,000 and 8,000. 

 Somatic protoplasts almost globose; 4 to 9.5 /x in diameter; widely 

 separated in the front and grading to much closer at the back of 

 the coenobium. Gonidia, 1 to 8 ; reaching 53 to 75 fi in diameter; 

 in pairs of different sizes ; the largest pair on opposite sides of 

 the middle of the coenobium; other pairs successively smaller; the 

 second of two pairs usually in the back of the coenobium; the 

 second of three or four pairs usually in the middle of the coeno- 

 bium between the first pair. Gonidia of daughters sometimes 

 divide and produce granddaughters that are the beginning of 

 the fourth generation while the daughters are still within the 

 mother. Daughter coenobia strongly ovoid and more or less 

 flattened by mutual pressure. Granddaughters at first spherical. 

 Bisexual coenobia producing 2 to 6 antheridia with 12 to 43 

 oospores. Oogonidia more numerous and smaller than gonidia 

 in sister coenobia. Oospores with thick smooth walls ; diameter 

 about 43 to 45 ^ Female coenobia like the bisexual. Male coe- 

 nobia with between 100 and 400 antheridia ; androgonidia smaller 

 than oogonidia of same or sister coenobia; front of coenobium 

 without reproductive cells. Antheridia in the form of platelets 

 or shallow cups. Spermatozoids not described. 



Habitat— Albert Nyanza, Africa (leg. R. T. Leiper, 1907) ; 

 Ussangu Desert, German East Africa (leg. A. W. Jakubski, 

 1909-10) ; fresh-water pools near Manila, Philippine Islands 

 (leg. W. R. Shaw, 1914) .* 



• Slide mounts of material of this species from the vicinity of Manila 

 have been sent to Prof. Douglas H. Campbell, Stanford University, Cal- 

 ifornia, and to Prof. Frank G. Haughwout, Bureau of Science, Manila, P. I- 

 Material bottled in glycerine has been sent to sixteen biologists in Europe 

 and Asia and to sixteen in America. Duplicates of this bottled material 

 are available for distribution from my United States address: Claremont, 

 California.— W. R. S. 



