Feb., 1920] The Protozoa of Mirror Lake 103 



Trinema enchelys (Ehrenberg). 



This species was infrequent in a collection of alga-covered 

 poplar roots taken late in November from Station D. 



Length 36/x; breadth 16^t. 



Cyphoderia ampulla (Ehrenberg). 



This form was rare in one collection made on January 30 

 at the point where the spring water enters the larger pond 

 (Station E). 



Length 128iu; breadth 48^i; diameter of mouth 14^. 



Pamphagus hyalinus (Ehrenberg). 



On the sand at Station F in December, this form was 

 abundant. The pseudopodia were altogether hyaline. 



Diameter 32fx. 



Cochliopodium bilimbosum Auerbach. 



This species was abundant during February in algae from 

 the bowl of the spring (Station J). Late in March it was 

 common on the fine black sediment at Station M. 



Diameter 25-48/^. 



SUBCLASS HELIOZOA. 

 Order Aphrothoracida. 



Actinophrys sol Ehrenberg. 



Throughout the period of study, this form was abundant 

 in the bowl of the spring (Station J), at the point at which the 

 spring water enters the larger pond (Station E), and in algae 

 from a submerged stone at (Station G). 



Diameter 45-80iLi. 



Actinosphaerium eichhornii Stein. 



Five individuals of this species were taken, but no two of 

 them from the same station. In the latter part of October, the 

 largest specimen was taken on the green sediment at Station A, 

 another was found on the black sediment at Station B, and 

 still another one occurred on the bottom at Station F. In 

 November, an individual was taken in floating Spirogyra 

 (Station C) and another on the sand at Station E. 



Diameter 119-608^. 



