THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Vol. IV. 



Boston, March, 1883. 



No. 3. 



FtG. 9. — a, A Filament in Fruit; i, Resting Spores; c, Spore Ruptured and Cell escaping. 



An Al^a in an Aquarium. 



A species of fresh-water alga, grow- 

 ing in my aquarium the past season, 

 has interested me very much by its 

 peculiar method of fruiting. Conju- 

 gation is effected between two adjoin- 

 ing cells cf the same filament ; on 

 the side of each cell, near the end, 

 appears a small protuberance (fig. 9. 

 t/) ; these grow and gradually curve 

 toward each other until their ends 

 meet (<?), when thev fuse together and 

 enlarge to a circular, or rather oval, 

 cavity, (/) into which the contents of 

 the two cells flow, and a spore is 

 formed. The filaments then decay 

 and the spores, now enclosed in a 

 brown, cellulose envelope, are to be 

 found at the bottom of the jar. 



After a few months of rest the 

 spore begins to swell slightly, and 

 nuclei — usually two — can be seen 

 through the brown, outer coating. 

 .A.fter a time this is ruptured and there 

 issues from the cellulo:::e envelope a 

 transparent cell filled with green en- 

 dochrome ; this single cell gradually 

 grows and subdivides, forming long, 

 green filaments. 



E. L. Cheeseman. 



Knowlesville, N. Y. 



[The alga described by our corres- 

 pondent is a species of Mesocarpus\ 

 the specific name could not be deter- 

 mined from the description and the 

 drawing sent. Rabenhorst distin- 

 guishes between Mesocarpus, which 

 fruits by the conjugation of cells of 

 different filaments forming the spores 

 between them, (not as in Spirogyra, 

 Zygnsfna, etc., in the cells of one of 

 the filaments) and Fkurocarpus, which 

 conjugates as illustrated in fig. 9. The 

 two modes of conjugation are respect- 

 ively designated as scaliform, or lad- 

 der-like, and lateral. Kirchner has 

 grouped the two genera under one 

 genus, Mesocarpiis, Hass., and distin- 

 guishes between species with ladder- 

 like, and those with lateral conju- 

 gation. — Ed.] 



Improved Filtering Reagent 

 Bottle. 



BY C. E. HANAMAN, F. R. M. S. 



Having recently made some im- 

 provement in the " Filtering Wash-bot- 

 tle " described before the " Section of 

 Histology and Microscopy" of the 

 A. A. A. S. at Montreal last August, 

 I append a description and drawing 

 of the apparatus, which I think will be 



