268 Miss S. G. Foulke on some Phenomena in the 



XXXIV. — Some Phenomena in the Life-history of G\ix\\\x\x\'\.\\^ 

 elegans. By Sara Gwendolen Foulke *. 



While collecting Infusoria among Lemna and the leaves 

 of the yellow pond-lilj, in a ditch on Brandywine Creek, 

 Chester County, Pennsylvania, the writer was so fortunate as 

 to secure large numbers of that beautiful Heliozuan, Clathru- 

 lina elegans. 



This rhizopod was attached in myriads to the roots of the 

 Lemna^ the groups in many cases being composed of above 

 twenty-five colony-stocks, so matted together by the twisting 

 of the pedicels and so surrounded by waste matter as com- 

 pletely to conceal at that point the supporting root-tibre. 



The animals were in a most active condition, feeding by 

 means of their characteristic pseudopoJial rays, and multi- 

 plying so freely by self-division, that the water was full of 

 the Actinophrys-VikQ bodies, and almost every capsule sup- 

 ported from one to ten young individuals. 



After being kept in captivity for two weeks the large 

 social groups had decreased in number, altliough solitary 

 individuals were much more numerous. Ileproduction was 

 still going on, but not so freely and by more varied methods. 

 The phenomena exhibited during the act of reproduction are 

 the subject of this communication. 



The modes of reproduction are four in number, two of these 

 being slightly similar, while the others essentially differ in 

 character. I'hese four modes are : — fi'stj by division ; second^ 

 by the instantaneous throwing off of a small mass of sarcode ; 

 tliird^ by the transformation ot the body into flagellate monads j 

 SiXidiJourthj by the formation and liberation of minute germs. 



By X\\e,jfirst mode, and this is the most common, the sarcode- 

 mass within the capsule withdraws its rays, constricts, and 

 divides into from two to four granular masses, which, after a 

 varying period of rest, pass out from the capsule and instantly 

 shoot forth pseudopodiai rays on all sides, thus assuming the 

 appearance of an Actinoykrys sol. These Actinophrys-\\kit 

 bodies after a time develop a protoplasmic stalk or pedicel, 

 by which they attach themselves usually to the parent 

 capsule. A thin film of protoplasm is then thrown out and 

 subtended by the rays at a short distance from the body, and 

 this, by development and secretion, becomes the latticed 



* From the ' Proceedings of the Academy of Natural Sciences of 

 Philadelphia,' Jauuaiy 15, 1884, pp. 17-19. 



