1885.] 



MICROSCOPICAL JOURNAL. 



113 



of Chlamydococcus ^ oval or round, 

 with a closer envelope, entirely green 

 contents, a starch-granule, 2 vacuoles 

 and 2 cilia. 



Sexual propagation by copulation 

 of microgonidia. which form in in- 

 definite number in one mother-cell, 

 egg-shape, ofgreenish or yellow color, 

 with a hyaline end, a red spot, and 2 

 cilia. These may be distinguished 

 as male and female. The former 8 

 the latter 2-4 in a mother-cell. In 

 copulation the male cell is wholly 

 absorbed in the female. The zygo- 

 spore is thus produced and by re- 

 peated division, the daughter-cells 

 not being motile, into a Pleurococcus- 

 like resting condition. 



Asexual multiplication by division 

 of vegetative cells in 2-8 microgo- 

 nidia with 2-4 cilia, which go into a 

 resting condition. 



[ Chlamydojnonas resembles Chla- 

 mydococcus^ but the mature motile 

 cells differ as follows : — In Chlamy- 

 dococctis the envelope stands away 

 from the green contents ; in Chlamy- 

 domonas it is close. Chlamydococ- 

 cus has a red central portion ; Chla- 

 mydo7nonas has not. but sometimes 

 has a parietal red pigment spot. The 

 former also has well-defined stixrch- 

 vesicles.] 



47. Genus Step/ianosphceraQohn. 

 Family spherical, consisting of 8 



spindle-shape cells, regularly ar- 

 ranged in a circle, with green con- 

 tents and 2 cilia each, enclosed within 

 a hyaline sphere. 



Sexual propagation unknown. 



Asexual multiplication by division 

 of each vegetative cell into 8 daugh- 

 ter-cells which grow into new fami- 

 lies, as in Eudorina and Pandorina 

 (50.51). Also microgonidia with 4 

 cilia are produced, which, probably 

 after copulation, become red rest- 

 ing-cells whose contents, after dessi- 

 cation are transformed into 4-8 swarm- 

 cells (macrogonidia) each with two 

 cilia. These in turn give rise to new 

 families. 



48. Genus Gonhim Midler. 

 Families of 4-16 cells in a single. 



tabular quadrangular layer, enclosed 

 by a common gelatinous envelope. 

 Cells somewhat polygonal by mutual 

 pressure, enclosed by a delicate en- 

 velope, with green contents, a starch- 

 granule. 2 conti'actile vacuoles, 2 

 long flagella and a red spot. 



Sexual propagation unknown. 



Asexual by repeated division of all 

 vegetative cells forming new families. 



49. Genus Symira Ehrenberg. 



Families spherical, 2-32 wedge- 

 shape cells in grape-like families, of 

 brownish color, without pigment- 

 spot, without firm envelope, with 2 

 long flagella. 



Sexual propagation vmknown. 



Asexual by breaking up of the fam- 

 ilies into single cells ; these cells con- 

 tinue motile and produce new fami- 

 lies by division, or they become rest- 

 ing cells, surround themselves with a 

 gelatinous envelope and midtiply by 

 binary division. The growth of new 

 families from these resting cells has 

 not been observed. 



50. Genus Pandorina Bory. 

 Families spherical or nearly so, 



composed of cells aggregated together 

 in grape-like masses, the whole en- 

 closed in ample hyaline envelope. 

 Families of 16, 32 or 64 cells, some- 

 what angular by mutual pressure, 

 each with 2 flagella, green contents, 

 and usually with a red spot. 



Sexual propagation by pairing of 

 similarly shaped swarm-cells of dif- 

 ferent families. These form by the 

 division of all the cells of one family 

 in (usually) 8 swarm-cells, spherical, 

 green with a red spot and colorless 

 end, with 2 cilia. When set free 

 they copulate with other swarm-cells, 

 joining by their anterior ends, finally 

 fusing together, and form a red zygo- 

 spore. After a period of rest this 

 gives rise to 1-3 large macrogonidia. 

 each of these becomes quiet and pro- 

 duces a new family by division. 



Asexual propagation as in Eudo- 

 rina (51). 



B. — Copulation Sexual. 

 Families spherical, moving about 



