96 SUMMARY OF QUERENT RESEARCHES RELATING TO 



and structure of the Cklamydomonadmese, whicli lie regards as a sub- 

 diviflion of tlie Volvocinese, and to be separated from the Chrysomona- 

 dineaj, which belong properly to the animal kingdom. The points of 

 departure of the Volvocinese from the Chrysomonadineae is Polytoma 

 uvella Ehr., which does not possess the power of absorbing solid aliment 

 into its interior, but which has no chlorophyll. 



Very nearly related to Polytoma is Chlorogonium euclilorum Ehr., 

 under which name two species have hitherto been confounded, and the 

 conjugating form of which has been described by Ehrenberg as Dyas 

 viridis. A new genus and species Cercidium elongatum is described, 

 differing from Chlorogonium in having only two amyliferous corpuscles 

 stained a light blue by iodine, instead of five or six ; it is reproduced 

 sexually by gametes formed six in a cell ; the germination has not been 

 observed. In the same circle of affinity come also Phacotus angulosus 

 Stein (Cryptoglena angulosa Cart.) and Phacotus viridis Pert. 



The author's previous researches on Chlamydomonas and Chlamydo- 

 coccus * are then given more in detail ; and a new genus and species 

 described, Pithiscus Klebsii, nearly related to them, found among Gonium 

 and Pandorina. The body is barrel-shaped, enveloped in a thick mem- 

 brane ; at the base of a small conical anterior papilla are four cilia ; the 

 protoplasm is coloured an intense green ; there is a nucleolated nucleus, a 

 posterior amyliferous corpuscle, and a pigment-spot ; reproduction takes 

 place by two, four, or eight zoospores. To the same family belong also 

 Tetraselmis cordiformis Stein, Coccomonas Stein, and Chlorangium Stein. 



In the general review of the characters of the Chlamydomonadineaa 

 it is stated that they are distinguished by the presence of special bodies, 

 charged with the production of starch, the amyliferous corpuscles ; these 

 are usually one or two in number, occasionally five or six. There are 

 always two or three contractile vacuoles. Eeproduction takes place by 

 zoospores or by conjugation of zoogametes ; in the latter case the en- 

 velope of the gametes may contribute or not to the formation of the 

 zygote (zygosperm). In some genera the sexual mode of reproduction 

 is replaced by encystment. 



The author then proposes the establishment of a new family, the 

 PoLTBLEPHARiDE^, founded on a single new genus and species, Poly- 

 hlepharides singularis. Its internal structure agrees with that of the 

 Chlamydomonadinese, but it differs in its mode of multiplication, viz. by 

 longitudinal division of the body into two individuals ; cysts are also 

 formed. 



Under Volvocineae proper the author includes the genera Gonium, 

 Pandorina, Eudorina, Stephanosphaera, and Volvox ; the HydrodictyesB 

 (Hydrodictyon, Pediastrum, Sorastrum, and Coelastrum) forming quite a 

 distinct group. 



The provisional group Teteaspore.^ comprises the genera Gloeocystis, 

 Apiocystis, Schizochlamys, and Tetraspora, characterized by the property 

 of surrounding themselves by a mass of gelatin. They are reproduced 

 by biciliated zoospores ; conjugation of gametes takes place in Tetra- 

 spora, and the formation of cysts in Gloeocystis; they are chiefly 

 distinguished from the Chlamydomonadineee by the immobility of the 

 cell during the vegetative period. 



The Pleurococcaoe^, comprising the genera Pleurococcus, Dactylo- 

 coccus, BapMdium, Scenedesmus, and Nephrocytium,-\ are distinguished 

 * See this Journal, 1888, p. 1004. t Ibid., p. 1013. 



