Lake Maxinkuckee, Physical and Biological Survey 149 



24. BOTRYDIUM GRANULATUM <Linn?eus) 



Noted growing abundantly on the surface of cracking, moist 

 mud at the shore of one of Zechiel's ponds, the plants having the 

 appearance of small green shot. 



25. TRIBONEMA BOMBYCINUM (Agardh) 



Abundant along shore and common in numerous shore collec- 

 tions along with Hydrodictyon, Spirogyra, CEdogonium, etc., prob- 

 ably helping form the great mass of algse along the shore near the 

 Outlet. 



26. TETRASPORA LUBRICA (Roth.) 



Not found in the lake at all but very abundant in spring in 

 woodland ponds on the dead leaves which formed the bottom, where 

 it was collected by hand (April 27, 1901) , along with Draparnaldia, 

 Tolypothrix and Zygnema. Our material was from a small pond 

 near Farrar's. It is probably common in parts of the lake at cer- 

 tain seasons. 



27. BOTRYOCOCCUS BRAUNII Kuetzing 



Quite abundant in the plankton scum during the summer and 

 autumn of 1906, mixed in with a great amount of Anabaena flos- 

 aqime which formed the main mass. The colonies were of two col- 

 ors, yellowish green and bright red. On account of its vivid color 

 and commonness the plant excited an unusual interest and it was 

 studied somewhat in detail. The following notes were made: 

 Colonies rather solid, irregularly lobed masses, a rather large colony 

 measuring 250 x 120 mic. Margin of colony with minute but blunt- 

 ish, sometimes clavate, projections. In fresh material the structure 

 of the colony is difficult to make out satisfactorily on account of the 

 diffiused red color which renders it opaque. A colony of formalin 

 material was kept in a moist chamber for several days and much 

 of the coloring matter dissolved out in the form of oil-like orange- 

 red drops, leaving the margins of the thallus paler. 



The thallus was then seen to be a firm mass containing rather 

 widely separated oval or ovate lacunae (diameter of lacunae 7-10 

 mic. separated by spaces 7-10 mic. wide) . The vegetable cells had 

 escaped from the lacunae and were ovoid or pear-shaped, measuring 

 about 7 mic. across the short axis and 12 mic. along the long axis. 

 No cilia were visible. 



On account of its vivid color this species can be recognized 

 quickly among heterogenous material. It appears to be eaten in 

 considerable amounts by various entomostraca, the stomach con- 

 tents of which are colored red by it. 



