Aquarium Microscopy) 



PROFESSOR R. FRANCE 



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Paradise Fish, Macropodus vir idi-auratus, Three Days Old 

 Photomicrographs by Carl L. Hartshorn 



The aquarist has more than one rea- 

 son to wish to be the owner of a micro- 

 scope. The miniature life-community, 

 confined within the limits of his glass 

 tank, again and again presents to him — 

 not infrequently contrary to his desired 

 aim — revelations of the microscopic 

 world, be it in the form of a green cov- 

 ering on the sides of his aquarium 

 threatening its transparency, a mass of 

 fine green algae weaving a network 

 among his Vallisneria, Sagittaria and 

 other plants, or in the dark green or 

 brownish colored covering of the sand 

 of his old tanks, which may suggest to 

 him a cleaning and a rearrangement. 

 But apart from this disturbing interfer- 

 ence, the influence of the invisible "mi- 

 crocosmos" is apparent in many other 



ways. In feeding his fishes with Daph- 

 nia and Cyclops, in hunting for Hydra, 

 or in caring for his aquatic plants, a 

 microscope is a valuable aid and teach- 

 er, increasing the enjoyment in his pas- 

 time a hundredfold. 



Every aquarium is an inexhaustible 

 source of microscopic life and always 

 harbors a rich microscopic fauna and 

 flora. One never fails to find the dia- 

 toms, which have been called the "jew- 

 els of the plant world." as well as some 

 of the graceful desmids, unicellular 

 bright-green algae, of which Closterium, 

 Cosmarium and Micrasterias are fre- 

 quent kinds ; also the tiny and beautiful 

 Scfnedesmtis and Pediastrum, the latter 

 a relative of the peculiar water-net, 

 Hydrodictyon, will seldom be missing, 



