238 FRESH-WATER RHIZOPODS OF NORTH AMERICA. 



The animal feeds on infusorians, rotifers, unicellular algae, and zoo- 

 spores. Active animalcules, in coming into contact with the rays of Actino- 

 phrys sol, in most instances appear to become more or less paralyzed. The 

 smallest infusorians or algxe brought into contact with the rays glide 

 slowly along them to their base. Larger and more active animalcules and 

 zoospores, coming into contact with the rays, will cause several together to 

 retract and draw the food to the body. When near or in contact with the 

 latter, a portion of clear protoplasm is projected to involve the prey, in 

 quantity according to the size and struggles of the latter. 



Fig. 1, pi. XL, represents an individual, which, with others, was sur- 

 rounded by a multitude of bright green, actively moving zoospores.* As 

 one of these came into contact with the rays of the Actinophrys, it became 

 instantly motionless. Gradually the zoospore was drawn inwardly by 

 means of one or more retracting rays, and, when within a short distance 

 of the body of the Actinophiys, a portion of clear protoplasm was pro- 

 jected to receive it. Becoming involved in the process of protoplasm, 

 this, together with the zoospore, was slowly withdrawn into the interior of 

 the Actinophrys, where, within a clear globule, it assumed the shape of a 

 green ball. In the process of digestion, the green balls became brown, 

 and occasionally in this condition one would gradually approach the 

 surface of the Actinophiys and suddenly be expelled. 



Fig. 2 represents an Actinophrys sot, which, while under examination, 

 received upon its rays an active Euglenia. This, in its struggles, produced 

 much disorder among the rays of its captor, but withal was drawn 

 toward the body and received by a large Aoav of clear protoplasm. The 

 Euglenia continued its struggles, which caused a greater effusion of the 

 latter. At one moment it appeared as if the Euglenia would escape, 

 but it became enveloped in an effused mass of protoplasm, which nearly 

 extended around the semi-diameter of the body of the Actinophrys, and 

 finally ceased all movements. The exuded protoplasm then gradually con- 

 tracted into a hemispherical form, as seen in fig. 3, including centrally the 

 Euglenia, now compressed into a ball. The pseudopodal protoplasm, con- 

 tinuing to contract, was slowly withdrawn, together with the Euglenia ball, 



* I do not know whether these are really zoospores or infusoria. They are bright green, oval, 

 with a central nucleus, and a colorless beak at one pole, but without ilagellum. They measured 0.010 

 mrn. by 0.012 mm. 



