510 Philippine Journal of Science »» 



The foregoing descriptions form the basis for the following : 



DIAGNOSIS OF GENUS AND SPECIES 



CAMPBELLOSPHAERA genus novum 



(Volvocaceae, Volvoceae) 



Body a spherical or spheroidal coenobium of biciliate cells 

 which contain chloroplasts. The cells appear to lie in the pe- 

 riphery of a gelatinous matrix surrounded by a hyaline envelope 

 through which the cilia extend. Somatic protoplasts globose or 

 ovoid, each enclosed in a thick gelatinous membrane which is 

 prismatic in form with truncate interior end and more or less 

 rounded exterior end. No protoplasmic filaments connecting the 

 protoplasts. Asexual reproduction by gonidia, differentiated in 

 early embryonic stages, which migrate from without into the 

 interior of the embryo through the phialopore before closure. 

 The gonidia are distributed and held in place by their thickened 

 gelatinous walls. They develop to relatively large size before 

 segmentation. Sexual reproduction by oospores which are more 

 numerous and smaller than the gonidia, and are usually formed 

 in the same coenobia with antheridia. Antheridia less numerous 

 than the oogonia, in the form of platelets. Spermatozoids elon- 

 gate, probably with terminal cilia. 



CAMPBELLOSPHAERA OBVERSA sp. nov. 



Coenobium spheroidal or more or less elongate; dimensions 

 commonly less than 500 p. Number of somatic cells mostly be- 

 tween 2,000 and 3,000; protoplasts globose, about 5 /x in diameter; 

 cell membranes very convex on the outer side. Gonidia, usually 

 8, 7, or 6, sometimes fewer, seldom more, arranged in quartets, 

 or pairs, or a quartet and one or two pairs, in graded sizes ar- 

 ranged symmetrically with respect to the polar axis of the coe- 

 nobium; those of the posterior pair or quartet the largest and 

 segmenting first, those of the anterior pair or quartet smallest 

 and segmenting last. Gonidia, 15 to 18 p in diameter when 

 differentiated, attaining diameters of 50 to 90 ft before dividing. 

 Daughter coenobia developing their gonidia to large size before 

 birth. All daughters born through one hole formed by loss of 

 somatic cells in a circular area about the posterior pole. Asexual 

 and sexual daughters formed in the same mother coenobia. 

 Sexual coenobia monoecious. Gametangia more numerous and 

 smaller than the gonidia, largest number, about 30 ; diameters, 

 about 12 to 14 p when first differentiated, becoming about 29 to 

 37 p in diameter; the smaller becoming antheridial platelets of 

 128 sperms, the larger more numerous and becoming oogonia. 



