144 MICROSCOPY FOR BEGINNERS. 



5. DINOBRYON (Fig. 110). 



In the early spring, as early as March, among the 

 Algae then found so abundantly in the shallow pools, 

 colonies of very small, vase-shaped loricse are often ob- 

 tained. They are sometimes attached to a plant or fila- 

 ment of alga, or as often they float freely through the 

 water, being fastened to the plant by a very slight hold. 

 The loricae are transparent and colorless, and may be 

 overlooked, but the Infusorium within each 

 one is rather conspicuous to even a low-pow- 

 er objective, for it has a narrow green band 

 on each side of the body, and often a minute 

 red eye-like spot in the centre of the front 

 border. The loricse are united together by 

 one or two being attached to the front edge 

 of the one behind them, until branching colonies of 

 some size are formed. The front border of each en- 

 closed Infusorium bears two flagella, one long and one 

 short, but they are seen with difficulty even with a mod- 

 erately high-power objective. The lashing of all the 

 flagella in a large colony urges it quite rapidly through 

 the water. According to my experience Dinobryon is 

 seldom found in the summer. 



6. VAGINICOLA (Fig. 111). 



The lorica is colorless, transparent, and about three 

 times as long as broad. In form it is long, vase-shaped, 

 or nearly cylindrical, the base, or the part fastened to 

 the plant or other object, being usually rounded. The 



