42 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



Pandorina Bory. Coenobium spherical, covered by a 

 colorless jelly. Cells 8, 16, or 32, green, spherical, each covered 

 with a thin membrane and furnished with two widely divergent 

 cilia, often so crowded as to be angular. Propagation sexual, 

 by the conjugation of isogamous gametes. Cells of a coenobium 

 divide into eight daughter-cells ; these become two-ciliated 

 gametes, and are scattered and conjugate with similar cells 

 from other coenobia ; they flow together and produce a 

 zygospore, which, after a season of rest, develops one to three 

 biciliate macrospores, and these in their turn develop new 

 coenobia. Asexual multiplication by formation of a daughter- 

 ccenobium from each of the cells of the mother-coenobium. 

 P. morum (Mull.) Bory, Figs. 286, 287. 



SUB-FAMILY II. CHLAMYDOMONADE^. 



The plants are unicellular, spherical or ovoid, with thin 

 walls, and two or rarely four cilia. The chloroplast is in the 

 posterior end of the cell and usually contains one pyrenoid. 

 Reproduction by division of the resting cell into 2, 4, or 8 

 daughter-cells. Non-motile spores sometimes occur. Sexual 

 reproduction by conjugation of ciliated gametes, either isoga- 

 mous or heterogamous, which are similar to the vegetative 

 cells, though smaller. They arise by division of the contents 

 of the mother-cell, sometimes as many as 64 resulting from one 

 cell. 



Key to Genera. 



Contents of cell close to cell wall Chlamydomonas* 



Contents of cell connected with cell wall by threads 



Spharella 



Description of Genera. 

 . Chlamydomonas Ehrb. Vegetative cells ovate, green, 

 enclosed in a narrow, colorless tegument, frontal extreme some- 

 times produced to a beak with two cilia, other end with large 

 chloroplast, and with or without a red lateral spot. Gametes 

 formed by continued division of cell contents of vegetative 

 cells, numerous, oblong, or ovate, pale green or yellow, after- 

 wards brownish. Zygospores globular, red or brownish. 



Chlamydomonas is abundant in the reservoirs of the state. 



C. pulvisculus Ehrb., Fig. 289. 



