THE ASEPTIC CULTIVATION OF MYCETOZOA. 63 



from a flask culture, placed on the slide, and immediately 

 examined,, the vacuoles are not always found. In favorable 

 cultures the zoospores are found creeping on the slide and 

 changing their shape; the flagellum is in active motion. At 

 the posterior portion of the body a pseudopodial prolongation 

 is put out, by means of which they adhere to the slide. Not 

 far from the attachment of the flagellum there arises a pro- 

 jection, which is placed more or less perpendicular to the surface 

 of the body. At first sight it appears to be simply a conical 

 or papillary projection from the surface layer of protoplasm. 

 On closer examination a thin fold of protoplasm is seen to 

 arise from the whole length of the projection, and extends 

 forward toward the flagellum, where a second similar projec- 

 tion arises. At this stage tlie two projections, with the thin 

 fold-like connections, form a funnel-shaped depression. The 

 apices of the two projections approach each other and fuse, 

 converting the funnel-shaped depression into a closed vacuole, 

 which passes backward, and is lost among the vacuoles near 

 the centre of the body. The flagellum is in active motion, 

 and throws the bacteria or particles of carmine into the funnel- 

 shaped depression, which then closes and forms the vacuole. 

 The writer has seen bacteria and particles of carmine taken 

 up in this way. When these vacuoles are located in the 

 posterior region of the body, the flagellum has not been 

 observed to throw the bacteria into them. Fig. 12, a — j, shows 

 the diff'erent stages in the formation of these vacuoles. The 

 zoospores of Phys. cinereum have not been observed to form 

 these vacuoles. 



The amoeboid stage of the zoospores of Phys. cinereum is 

 much more pronounced than that of Stemonitis A, B, C, and 

 Cerat. porioides. A large part of the active existence of the 

 zoospores of Phys. cinereum is passed without the presence 

 of flagella. They put out pseudopodia which are more or less 

 angular, and their change of shape resembles more that of an 

 amoeba. They may ingest their food after the manner of amoebae. 



The zoospores of Stemonitis A, B, C, and of Ceratium 

 porioides are characterised by rarely being without a fla- 



