6 BRITISH FKESHWATEH RHIZOPODA. 



and certain of the Amoebae, in which often no ectoplasm 

 can be distinguished. Under certain circumstances 

 even here, " such a hyaline external plasma-layer makes 

 its appearance, and this consequently must have been 

 produced from the granular plasma in the way in 

 which, locally bounded, a hyaline pseudopodium is 

 evolved from the body of a Rhizopod consisting of 

 granular plasma." Concerning the external limita- 

 tions of the Rhizopod body, he says that it is naked, 

 "but it would appear that by contact with water," as 

 Dr. Wallich had previously shown, " a stiffening of the 

 plasma takes place at the periphery, preventing its 



FIG. 1. Portion of the periphery of Pelomyxa palustris when at 

 rest, with the endoplasm (en) and ectoplasm (ec) sharply denned 

 as frequently seen, and an oiiter fringe of minute projections 

 from the latter, x about 150. 



deliquescence, and also causing an immediate closure 

 of the cut surface, in case of artificial division. When 

 the protoplasm issues forth in a broad process, in the 

 form of pseudopodia, the former bounded portion dis- 

 solves in the advancing plasma, to become re-formed at 

 the same moment." 



This author acknowledges the prior claim of Dr. 

 Wallich to the discovery. Dr. Wallich was also the 

 first to explain the production of the nutritive vacuoles, 

 by assuming that a drop of water is carried in along 

 with the incepted food-particles, and that this exerts 

 the known stiffening action upon the portions of plasma 

 surrounding thebodies incepted, "so that every nutritive 

 vacuole appears to be lined with an ectosarcal layer." 



