334 THE JOUENAL OF INDIAN BOTANY. 



This invasion by the free swimming Chlamydomonas of a wet 

 sub-aerial region, in the first place, and, in the second place, its losing 

 its cilia under a comparatively drier condition, suggests a probable 

 method by which some of the sub-aerial unicellular Green Algae might 

 have evolved from some free swimming Chlamydomonadine type. 



Genera collected 



The following genera have been collected by me at Madras : — 

 Chlamydomonas, Carteria ; Gonium, Pandorina, Eudorina, Pleodorina 

 and Volvox. The most common ones were Chlamydomonas and Car- 

 teria among the unicellular forms, and Pandorina and next Eudorina 

 among the coenobial forms. Gonium was a rarer form. Pleodorina 

 was still rarer. But the rarest was Volvox. 



These forms I must however point out were always associated 

 with a sprinkling, large or small, of other plankton forms of Algae, and 

 Flagllate (such as Euglena, etc.). 



One feature which was particularly noticeable in the summer 

 rain-water pools was the complete absence of Spirogyra and the other 

 filamentous Green Algae, and the extreme scarcity of the Blue Green 

 Algae. 



Enemies of the Volvocaceae 



The bottom of the pools very often showed large numbers of 

 amoebae ; and these injested a large number of the unicelluler algae 

 during the times when the latter settled down at the bottom. I came 

 across many amoebae, with Chlamydomonas in their bodies and I 

 saw some actually in the act of in jesting them. 



In another pool I found Pandorina and Eudorina swimming with 

 one or two, sometimes even four, or five, small round colourless 

 Protozoons attached to their mucilaginous envelope. On further exa- 

 mination I found that these Protozoons gradually made their way in- 

 side and swallowed some of the cells of the colony. Later on they 

 escaped from the colony leaving a big rent in the mucilaginous enve- 

 lope. Many specimens of Pandorina and Eudorina were found by 

 me with a big rent in their body and a few of their cells missing. 



Another enemy which plays havoc with these forms is a kind of 

 Eotifer. This was found in very large numbers in a tub containing 

 Pleodorina and Eudorina devouring them in large numbers. 



I came across a Chironomus larva ("Blood-worm"), devouring 

 large quantities of Pandorina. This larva has the habit of constructing 

 out of the materials of its environment such as silt, etc., a kind of case 

 for itself by fastening with the help of a silk-like secretion of its sali- 

 vary glands. I kept some quantity of live Pandorina in a dish. The 

 next morning I found a large number of green cases attached to the 



