462 Annals of the South African Museum. 



Number of oospores, 130 to 227. 

 Size of sperm globoid, 30 to 43 /JL. 



Size of oospore with spines, 44 to 46 /A ; without spines, 35 to 38 

 spines, 5 to 7 /JL. 



E. Volvox amboensis sp. nov. 



We proceed next to describe a Volvox we obtained from Ovam- 

 boland ; this, though resembling V . Rousseletii in many ways, differs 

 from it rather markedly, and we have decided to institute for it a new 

 specific name. We have been able to observe it only in preserved 

 material, and from one collection, and we have not been able to obtain 

 satisfactory photographs, as the large coenobia are very fragile and 

 readily collapse. The name amboensis is proposed to indicate its 

 occurrence in the land occupied by the Ovambo tribes. 



Coenobiis asexualibus late ovoideis, 220-1300 yu, (plerumque 800- 

 1000 n) latis, cellulis ca. 30,000-50,000, in parte posteriore densiore 

 aggregatis ; coenobiis infantibus 1-14 (vulgo 8), interdum in coenobiis 

 sexualibus inclusis. Coenobiis sexualibus majoribus, usque ad 2 mm. 

 latis, bisexualibus ; ovoideis ; antheridiis 31-33 /it latis ; oosporis 

 numerosis (ad 700) arete congestis, in ca. tertiam parteni coenobiis 

 carentibus (interdum in utroque polo absentibus), sine spinis 30-34 [JL, 

 latis, spinis cavis, conicis, acutis, ad 5-7 ^ longis obtectis. 



Collected by Dr. K. H. Barnard in February 1921, and by Dr. 

 Barnard and Dr. R. F. Lawrence in February 1923, from Ongka in 

 Ovamboland, South-West Africa. Dr. Barnard states that he visited 

 the water-hole in which it occurred on two separate occasions, 

 and that both times the water was green with the Volvox (no 

 filamentous algae were present). The locality is about 15 miles north 

 of Ondongua. 



This is a large and very variable Volvox with an astonishingly large 

 number of oospores. The asexual coenobia are broadly ellipsoidal in 

 shape and vary in size, a large one measuring 1200 x 1300 /x. The 

 number of cells has been roughly computed as from 30,000 to 50,000 ; 

 they are densely packed at the posterior end. The somatic proto- 

 plasts are pear-shaped in side view (text-fig. 6, C). The protoplasmic 

 processes are difficult to see (the materiaJ is preserved in alcohol) ; 

 stained with gentian violet they appear as fine strands, sometimes 

 anastomosing (text-fig. 6, B). The two cilia are inserted near together 

 at the pointed end, which reaches nearly to the surface of the common 

 envelope. There is one pyrenoid in each cell, large and nearly filling 



