264 University of California Publications in Zoology [Vol. 16 



The part of the protoplasm protruded is very much lighter stained 

 than that within, which may be partly due to the fact that it is exposed 

 and hence destains easily. It is much less dense than that within the 

 cyst (pi. 21, fig. 89). Vacuoles may be foimd in the cytoplasm within 

 or without the cyst or in both places (p). 21, figs. 89, 90; pi. 23. fig. 

 111). The karyosome is always compact and stains very dark. 



The flowing out may continue after the pseudopodia are protruded 

 or it may not proceed further for thirty-five minutes or longer. After 

 it does begin again it is nearly continuous until the amoeba is out. 

 An amoeba has been observed to flow back part of the way, then out 

 (ef. pi. 23, figs. 110-112) , and this may be repeated several times before 

 it emerges. The process may require from seven to thirty-five minutes 

 and even longer. The series figured (pi. 23, figs. 107-113) was com- 

 pleted in seven minutes, but a large amount of protoplasm was 

 extruded before the drawings were begun (pi. 23, fig. 107). 



Often amoebas are foimd emerging at two or three exits. It is 

 very common to find them protruding from two (pi. 21, fig. 88). 

 Usually the protoplasm extends a little way out as in figure 88, then 

 flows out at one, having flowed back in from the others. Occasionally, 

 however, individual conditions are found in which a large mass has 

 flowed out at two openings (pi. 21, fig. 90). 



That there are two layers in the wall of the cyst is evident from 

 development stages, as before mentioned, and the outer wall serves as 

 a covering for the "pores" (Dangeard, 1910), or "cyst markings" 

 (Wherry, 1913) which are found in the inner thick wall. This outer 

 thin wall is probably easily broken or dissolved. This may be accom- 

 plished by the force of the products from the vacuoles which are pulsat- 

 ing frequently prior to exeystment or the protruding pseudopodia may 

 break through or may dissolve the outer wall locally. 



The number of pores may be readily counted in the abandoned cyst. 

 In those counted there have been from three to eight of these. What 

 the fate of the old wall is has not been ascertained, but they have been 

 observed intact two and three weeks after they were abandoned. 



III. THE FLAGELLATK 



A flagellate stage was fir.st found in this species, Naegleria gruieri, 

 by Schardinger (1899), who called the organism Amoeba gruberi, as 

 has been stated previously. Wherry (1913) also experimented with the 

 flagellate and other stages of what appears to be this species, from the 

 city water-supply of Oakland, California. 



