94 



aquatic flttf 



smallest of the genus, a row of dots is 

 noticed on one side but not on the other, 

 except when the two valves are seen to- 

 gether. (Fig. 7.) 



In all of the above forms there are 

 more or less distinctly marked transverse 

 lines, but they are scarcely noticed except 

 under high magnification. 



Certain other diatoms will probably 

 be found in aquaria at different times but 

 the above species appear to be constant. 

 I have repeatedly transferred other spec- 

 ies from streams or ponds to an aquar- 

 ium but they all disappear except these 

 minute forms. 



It is to be understood, of course, that 

 in the collection of material only that 

 which occurs or has occurred as a living 

 film on the walls of the aquarium should 

 be gathered as the valves which lie on 

 the surface of the sand will, in many 

 cases, include dead forms from the water 

 supply which will vary in different locali- 

 ties. 



If this article should receive the at- 

 tention of distant observers it might be 

 possible to determine whether there is 

 a diatomaceous flora, constant to aquar- 

 ian habitat. 



Result of Feeding Trout 

 on Dried Flies 



The use of imported dried flies in feed- 

 ing young trout has been experimentally 

 undertaken at several hatcheries of the 

 U. S. Bureau of Fisheries. Reports of 

 the comparative tests recently made at 

 the Green Lake (Me.) station indicate 

 no better results than earlier trials else- 

 where gave. 



Superintendent Race at Green Lake 

 set aside four troughs, each 12 feet long, 

 1 foot wide, and 8 inches deep, and into 

 each trough counted 930 brook-trout fry 

 that had not previously taken food. This 

 number was selected instead of 1000 be- 



cause 930 fish were found to weigh 3 

 ounces. The fish in two troughs were 

 fed exclusively on dried flies, and those 

 in two troughs exclusively on beef liver. 

 Feeding began on May 20 and the experi- 

 ment was discontinued on June 18, when 

 the fishes were planted. The results were 

 as follows : 



The lots of fish fed on dried flies 

 gained sixty-six and two-thirds per cent, 

 in weight in the month and sustained a 

 mortality of forty-one and three-fourths 

 per cent. The liver-fed fish gained 800 

 per cent, in weight and showed a death 

 rate of eight and one-third per cent. 



For the coming season the Chicago 

 Aquarium Society has arranged a pro- 

 gram that promises lively and interest- 

 ing meetings. Dr. H. C. Champlin has 

 succeeded Fred G. Orsinger as presiding 

 officer. The meetings are held at the 

 Keedy Studio, 367 North Dearborn 

 street. — W . P. 0. 



The tadpoles of frogs and toads are 

 rather remarkable for their ability to re- 

 place lost parts, and continue to grow 

 after serious injuries. Eight and ten-leg- 

 ged frogs, two-tailed tadpoles, and other 

 monstrosities have been produced by 

 splitting embryonic structures. It is aho 

 possible to form composite tadpoles by 

 grafting parts of different individuals to- 

 gether. — General Zoology (Pearse). 



The people who are hard to get along 

 with are those who object to our having 

 our own way. 



"Never hear much about malaria out 

 this way any more?" "No," answered 

 Uncle Bill Bottletop. "Malaria gets ter- 

 rible unpopular when there is nothing to 

 cure \ 4 - with except quinine." — Kansas 

 City Star. 



