1884.] NATURAL SCIENCES OF PHILADELPHIA. 1*7 



SOME PHENOMENA IN THE LIFE-HISTORY OF CLATHRULINA ELEGANS. 

 BY SARA GWENDOLEN FOULKE, 



While collecting infusoria among Lemna and the leaves of 

 the yellow pond-lily, in a ditch on Brandywine Creek, Chester 

 county, Pennsjdvania, the writer was so fortunate as to secure 

 large numbers of that beautiful Heliozoan, Clathrulina 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 completely 

 to conceal at that point the supporting root-fibre. 



The animals were in a most active condition, feeding by means 

 of their characteristic pseudopodial rays, and multiplying so 

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

 like bodies, and almost eveiy capsule supported from one to ten 

 young individuals. 



After being kept in captivity for two weeks, the large social 

 groups had decreased in number, although solitary individuals 

 were much more numerous. Reproduction 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 difl'er in char- 

 acter. These four modes are : Jirst, by division ; second, by the 

 instantaneous throwing off of a small mass of sarcode ; third, by 

 the transformation of the body into flagellate monads ; and 

 fourth, by the formation and liberation of minute germs. By the 

 Jirst 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 pseudo- 

 podial rays on all sides, thus assuming the appearance of an 

 Actinophrys sol. These Actinophrys-like bodies after a time 

 develop a protoplasmic stalk, or pedicel, by which they attach 

 themselves, usually to the parent capsule. A thin film of proto- 

 plasm is then thrown out and subtended by the rays, at a short 

 distance from the body, and this, by development and secretion, 



