Igg The Philippine Journal of Science 1923 



stage in the development of the asexually produced embryos, 

 and they seem to form a natural group. 



The most unique of these species exhibited a migration of the 

 gonidia from the outside to the inside of the embryo through 

 the phialopore shortly before the closure of that opening in the 

 wall of the forming sphere. That species I have described 

 (Shaw, '19) under the name Campbellosphaera obversa. 



A species, so similar to Campbellosphaera obversa that for a 

 long time the two were confused in my notes, was found to lack 

 the migration of the gonidia and to possess other distinctive 

 characters, and was proposed for the type of another genus, 

 Merrillosphaera (Shaw, '22B). This species proved identical 

 with Volvox carteri Stein ('78 V. globator Carter '59), and the 

 largest Philippine form was described under the trinomial 

 Merillosphaera carteri var. manilana. It was pointed out that 

 Volvox weismannia (Powers, '08) is at most another variety 

 of the same species, and that one of the forms described by 

 Klein ('89B) from material collected by Migula may be 

 regarded as another species under the name migulae. 



In Volvox africanus from Albert Nyanza no protoplasmic con- 

 nections between the protoplasts were observed by West ('10), 

 and none have been found in my numerous collections of the 

 species. My material reveals the fact that the gonidia are 

 differentiated at an early stage of the embryonic development 

 and attain a large size before segmenting in their turn, but 

 do not migrate through the phialopore of the embryo. Mainly 

 on the ground of these characters I assigned the species to 

 the recently erected genus under the name Merrillosphaera 

 africana. 1 



ORIGINAL DESCRIPTION AND ILLUSTRATIONS 



The original description by West was based on asexual ma- 

 terial obtained from Albert Nyanza by Mr. R. T. Leiper in 

 1907, and sent to West by Dr. W. A. Cunnington and Mr. C. 

 F. Rousselet. It was illustrated by three photomicrographs 

 (West, '10, pi. 3, figs. 8 to 10) that are herewith reproduced 2 

 on a larger scale (Plate 7, figs. 48 to 50) . These show ovoid 

 coenobia with dimensions, as indicated by the stated magnifi- 



*A preliminary announcement of this was made in a footnote to a 

 previously published paper (Shaw, '19, p. 512). 



'Through the kindness of Prof. R. H. Yapp and Miss Nellie Carter, 

 of the botanical department of the University of Birmingham, photographic 

 prints from West's negatives have been provided for the reproduction of his 

 figures with this paper. 



