GENUS DINAMCEBA— DINAMCEBA MIBABILIS. 89 



and the two portions of the alga approached so as to project from the ani- 

 mal at an acute angle, while at the same time the right portion was observed 

 slowly to sink into the interior (16). The animal next turned to the 

 left, the two portions of the alga assumed a position at a right angle, and 

 the left portion broke into two (17). The animal then turned until the 

 head was directed backward, and the two portions of the alga remaining 

 in connection with the animal assumed a parallel position close together on 

 the left of the tail end (18). What had been the left portion of the alga 

 sunk gradually into the body and disappeared (19). Subsequently what 

 had been the head of the animal shrunk and became the tail end furnished 

 with pseudopods, while the previous tail end projected pseudopods and 

 moved in advance as the head end (20). The projecting extremity of 

 what had been the right portion of the alga broke off close to the animal 

 and was rejected (21), while the retained portion sunk out of sight. 



Some days later I had the opportunity of observing another Dinamoeba 

 in the condition represented in fig. 4, pi. VI. It was a fine, large specimen, 

 of ovate form, the third of a millimetre long by the fifth of a millimetre 

 broad. From the left of the posterior part of the body projected two divi- 

 sions of a Didymoprium, which no doubt had been broken apart, as in the 

 former instance. The two divisions of the alga assumed a symmetrical 

 position at the tail end, and afterward portions of each were successively 

 broken off, and the retained pieces were swallowed. 



Habitually Dinamoeba rejects excrementitions matters at one side of 

 the posterior papillary extremity; but I have repeatedly observed the animal 

 discharge the remains of food not only from other parts of the body, but in 

 two or three widely separated positions at once, as represented in fig. 7. 



Though Dinamoeba mirdbilis is a more sluggish animal than Amoeba 

 proleus, it appears to be more irritable. Disturbance generally causes it to 

 withdraw its pseudopods and contract its body, though slowly. A slight 

 shock, I have also noticed, will frequently cause it to discharge a portion of 

 its food contents, and this several times and at several points at once. 



An active specimen of Dinamoeba, from Atco, New Jersey, when first 

 noticed, was oval, 0.3 mm. in length by 0.2 mm. in breadth. After a moment, 

 from disturbance, it discharged a few cells of Didymoprium, at the same 

 time, from the right of the head and the left of the tail, and in a few 

 seconds afterward upward of twenty cells of the same alga from the 



