xv, « Shaw: Campbellosphaera 5 15 



still going. The appearance of the coenobia under the low 

 powers, and the characters of the protoplasts, protoplasmic fila- 

 ments and spores under the high powers, were so exactly like 

 the excellent figures of Klein ('89A and '90) and of Overton 

 ('89) as to engender in any one who studied the specimens with 

 the literature a feeling that Volvoces must be about the same 

 all over the world, and that both of the existing species have 

 been well described. It was evident that the specimens would 

 need remounting. Before demounting them, 1 took some notes 

 and measurements — and fortunately, for the specimens after 

 being remounted are not what they used to be. 



The most recent advance in our knowledge of Volvox has 

 come from the studies of Janet ('12 and '14) in France. In 

 a long paper he gave a monographic account of the genus in 

 which he incorporated and extended the membrane studies of 

 Meyer, and he followed that with a preliminary paper in which 

 he announced the discovery that the egg apparatus of Volvox 

 globator is not a unicellular oogonium, but that it is multicellular 

 and morphologically a dwarf coenobium. This fact will neces- 

 sitate careful study of the corresponding parts of other species 

 of Volvox and related genera. 



There are two well-marked groups of the higher Volvoceae: 

 (1) those Volvox species with protoplasts connected by proto- 

 plasmic filaments, namely, V. aureus, V. globator, V. perglobator, 

 and V. rousseleti; and (2) those without the interprotoplastic 

 connecting filaments, namely, V. spermatosphaera, V. tertius, 

 V. africanus, and V. carteri {V. weismannia). The species of 

 the second group are more or less megalogonidiate, and it is 

 those of this group that are more so with which Campbellos- 

 phaera is more closely allied. My present conception of the 

 relationships of the Volvoceae is represented by fig. 1. 



SUMMARY 



From fixed and living specimens collected near Manila, Phil- 

 ippine Islands, a new species of the Volvocaceae (subfamily 

 Volvoceae) , is described which I propose for the type of a new 

 genus under the name Campbellosphaera obversa. A type 

 specimen is described in detail and figured by photomicrographs. 

 It exhibits the most peculiar character of the genus, which is 

 migration of gonidia, formed early in the development of the 

 embryo, from the outside to the inside of the embryo through 

 the phialopore. The gonidia become very large before dividing. 

 The somatic protoplasts lack protoplasmic connecting fibers. 



