Lake Maxinkuckee, Physical and Biological Survey 99 



them no injury, and were gotten rid of when the turtles shed their 

 scutes. It sometimes forms a halo about the heads of small turtles, 

 in which case it was at first mistaken for Saprolegnia. It is usually 

 the head of the Musk Turtle that is affected. In this case it ap- 

 pears to do no harm, as the turtles are quite lively. 



Something very like this, probably the same thing, was ob- 

 served abundantly (August 6, 1907) on the shoulders of a dragon- 

 fly larva. 



14. VAGINICOLA sp. 



A species of Vaginicola, perhaps gigantea, was rather common 

 along the shore of the lake by Overmyer's hill, attached to algae, 

 October 28, 1906. There were at least 6 examples on one small 

 bunch of algae. The sheath was brownish and transparent. When 

 jarred, the animal retracted into the sheath, usually doubling up 

 somewhat into a sigmoid curve. 



15. TOKOPHRYA QUADRIPARTATA (Oparede & Lachmann) 



Common, intermixed with Opercularia irritabilis, on the ventral 

 scutes of a Musk Turtle, September 12, 1906. It was also found 

 to some extent of the back. 



16. OPHRYDIUM sp. 



By far the most abundant and conspicuous protozoan in the 

 lake was a species of Ophrydium which formed large blue-green 

 gelatinous colonies about the size of a hazelnut, or larger. These 

 semitransparent blue-green balls remain in about the same condi- 

 tion the year round. They are found abundantly wherever the 

 carpet chara grows, and are usually attached to it or to pebbles; 

 or, quite frequently, to mussel shells either alive or dead. Clear 

 colonies, remarkable for their unusual transparency, were found 

 on submerged pieces of tile, August and September, 1907. At cer- 

 tain times, as August 1, 1906, and August 1 and October 12, 1907, 

 great quantities are washed ashore. The colonies are sometimes 

 hollow, as were many of those washed ashore August 1, 1907. 



17. HYDRA OLIGACTIS Pallas 



Not frequently encountered in the lake. On October 31, 1906, 

 however, multitudes were found under leaves at the water's edge 

 on the east side, and on November 13 more were found in a similar 

 position. November 18 one was found attached to floating Wolf- 

 fiella in Norris Inlet. 



