Observations on the Genus Volvox in Africa. 441 



equatorial plane, the 2 smaller near the posterior pole but the 

 number varied from 1 to 6. In most cases where an unpaired daughter 

 occurred, the other member of the pair was represented by an abortive 

 gonidium. So far as could be seen the daughters themselves were all 

 asexual. The smallest colony seen with mature daughters measured 

 345 x 431 /ji, and contained a single well-developed daughter ; the 

 largest, 603 x 646 /x, with 4 daughters one of which measured 218 x 

 258 /JL ; each of these 4 daughters bore 2 + 2 gonidia in early stages 

 (2- to 4-celled) of division. 



This Volvox agrees very closely with the description given by West,* 

 except that no trace whatever of protoplasmic connections between 

 the cells in the adult colonies, or even in young colonies, could be 

 made out. (This is in accord with recent observations made by 

 Professor lyengar on a small form of F. africanus collected in Southern 

 India. f See also Shaw's remarks quoted above.) In unborn daughter 

 colonies, however, after treatment with methylene blue, a connection 

 between the cells is here and there observable ; this resembles the 

 state of things described by Meyer for V. tertius.% 



C. Volvox capensis sp. nov. 



Volvox monoicus ; coenobiis sub-globosis vel late ellipsoideis ; 

 coenobiis asexualibus majoribus usque ad 1-3 mm. latis, cellulis ca. 

 9000-23,000, plerumque 18,000-20,000, in parte posteriore densiore 

 aggregatis ; coenobiis infantibus 3-20, plerumque 6-10, saepe 8, in 

 planis duobus alternantibus, 170-430 ^u., plerumque 200-300 /j, latis; 

 coenobiis sexualibus usque ad 1 mm. latis, bisexualibus protandreis ; 

 androgonidiis 4-23, plerumque 6-10, similiter coenobiis infantibus 

 dispositis ; spermatozoidis 512 rarissime 256, in globoidis depressis 

 40-44 p. latis ; oosporis 60-160, plerumque ca. 120, diametro sine 

 spinis 37-49 /t, in parte tertia anteriore coenobii absentibus ; spinis 

 cavis conicis usque ad 5-8 fj, longis obtectis. 



This species is intermediate between V ' . globator and F. Rousseletii. 

 From the former it is distinguished by (1) greater size ; (2) larger 

 number of somatic cells ; (3) antheridia more numerous, developing 

 uniformly into depressed hollow globoids of 512 (rarely 256) spermato- 

 zoids, never into platelets ; (4) much larger number of oospores, 

 averaging 120 per coenobium as compared with 30 in V. globator ; 

 (5) spines of exine longer and stouter, less numerous as seen in optical 



* West, G. S., op. cit., 1918. t I" the press. 



I Meyer, Bot..Zeit., vol. liv, p. 200. 



