GENUS UYALOSPHENIA— HYALOSrHENIA TAPILIO. 137 



Not unfrequently specimens of the kind just described are seen with 

 one or more globular masses of granular matter, colorless or colored yel- 

 lowish or brownish, lying between the green sarcode ball and the mouth 

 of the shell, as represented in fig. 10, which I have supposed to be exere- 

 mentitious. In several instances I have seen an animal withdraw its pseu- 

 dopods, retreat deeply into the shell, retract its threads of attachment, and 

 assume the form of an oval or spheroidal ball. This would subsequently 

 discharge several masses of excrementitious matter of the kind indicated, 

 and become proportionately reduced in size. 



In many specimens with the sarcode in the condition of a quiescent 

 ball, the mouth of the shell appears to remain open ; in others it is closed 

 by a sort of gelatinoid operculum, as seen in fig. 11. In one instance 

 observed, as seen in fig. 9, the lips at the mouth of the shell were in 

 close apposition, and cemented together by the material of the oper- 

 culum. 



I have repeatedly met with specimens of H. papilio, as represented in 

 fig. 12, in which the shell contained nothing excepting a quantity of scat- 

 tered bright green chlorophyl corpuscles, in all respects like those ordinarily 

 observed in the sarcode mass of the animal. 



I have further repeatedly observed specimens in which the shell con- 

 tained a variable number of globular, granular, colorless corpuscles, of 

 nearly uniform size in the same specimen, but of different sizes in different 

 ones, as represented in fig. 13. The nature of these bodies I have not 

 determined, nor whether they actually pertain to the Hyalosphenia or 

 belong to some parasite, but I have suspected them to be spores of the 

 former.' 



H. papilio in comparison with many other rhizopods is of remarkable 

 uniformity in size, shape, and constitution. Though I have seen thousands 

 of specimens, from different localities, in mountainous regions, and nearly 

 at the sea-level, I have observed but trifling variation. I never have seen 

 anything like decided transitional forms, never any with the shell positively 

 colorless, and not one in any condition, whether of activity or quiescence, 

 in which the sarcode was devoid of the chlorophyl corpuscles. 



As previously intimated, and for the reasons given, I have considered 

 Hyalosphenia papilio peculiarly well adapted for study, and I have looked 

 hopefully forward to it as a means of throwing light upon the modes of 



