420 University of California Publications in Zoology [Vol. 19 



injury by rapid movements of the needle-point causes their disappear- 

 ance in that region of the body. They may be observed for a time 

 within small globules of the endoplasm which have flowed out along the 

 sides of the needle and become enveloped with a "protective mem- 

 brane." But if the outflow of the endoplasm is sufficiently rapid and 

 of such quantity as to prevent the formation of a membrane, these 

 large granules quickly swell and burst or otherwise disappear, and 

 the hyaline, liquefied endoplasm disappears leaving only the small 

 granules, which may remain for hours constantly in Brownian move- 

 ment. In one instance this dancing movement of the granules con- 

 tinued throughout part of an afternoon and evening, a period of 

 about six hours. 



Ectoplasm 



The outflow of endoplasm and disintegration of the organism from 

 incisions made abruptly or from other causes is generally rapid and 

 sometimes explosive. To prevent this sudden disruption and regulate 

 the rate of outflow of endoplasm, a method which has been previously 

 described (p. 416) was used. This method permits a careful study of 

 the ectoplasm and pellicle. The ectoplasm consists of a comparatively 

 thin, gel matrix with densely packed small granules of a dimension 

 similar to that of the smaller granules of the endoplasm. These ecto- 

 plasmic gramdes appear equally numerous throughout, closely approxi- 

 mating the pellicle on one side and the endoplasm on the other. Griffin 

 (1910a) describes similar granules in the ectoplasm of E. worcesteri 

 which, however, vary in size and appearance more than do these 

 granules. 



Frequently, there is evident a fairly definite boundary between the 

 ecto- and endoplasm but this condition apparently varies. If its out- 

 flow be not too rapid,- the endoplasm separates from the ectoplasm and 

 pellicle, sometimes leaving large areas that may remain intact for 

 several seconds. With further disintegration of such areas, the pellicle 

 and matrix of the ectoplasm quickly disappear, but the granules here, 

 like the "microsomes" of the endoplasm. may persist for several hours 

 in continuous Brownian movement. Plate 33, fig. 23, shows a portion 

 of ectoplasm with a frontal cirrus attached. The position of granules 

 on one side illustrates the manner of disintegration. 



A further discussion of the pellicle appears under the caption 

 "Experimental." 



