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THE POPULAR SCIENCE MONTHLY. 



CORRESPONDENCE. 



NOTE ON THE BREEDING HABITS OF 

 THE MUD-MINNOW. 



OUR very common " mud - minnow " 

 (Melanura limi, Agassiz — Silliman's 

 American Journal of Science, 1853, vol. xvi., 

 p. 135), which is found over a wide extent of 

 territory in America, and which, according to 

 Dr. Albert Giinther (" Catalogue of Fishes," 

 in the British Museum, vol. vi., p. 231), is 

 generically the same as the Umbra crameri 

 of Europe, presents some features in its 

 breeding habits which we have thought of 

 particular interest, and would be greatly 

 pleased to know if the European Umbra 

 crameri, which Dr. Giinther states inhabits 

 the " stagnant waters of Austria and Hun- 

 gary — neighborhood of Odessa," has identi- 

 cal habits ; or, if the difference of climate, 

 and character of the surroundings generally, 

 have caused a more or less noticeable varia- 

 tion in its habits, especially during the 

 spawning-season. We have not access to 

 any work, on the fishes of Central Europe, 

 that gives any details of their habits. 



As we have already described it (Ameri- 

 can Naturalist, vol. iv., pp. 107, 388, Fig. 86), 

 this little umbra is, " pure and simple," a 

 mud-loving fish, and more strictly so than 

 any other, unless we may except the eel 

 (Angnilla acutirostris). During the present 

 winter we have had unusually favorable op- 

 portunities for studying the fish during this 

 part of the year. In December, while the 

 weather was cool father than cold, with but 

 little ice, we found that hundreds of these 

 fish were being thrown out with the mud 

 then being scooped from the ditches of the 

 tract of meadow on the writer's farm. On 

 learning this, we had the mud carefully 

 taken out by shovelfuls and examined, to 

 learn the exact condition and position of 

 these fish. They were, when taken from 

 the mud, motionless, stiff, and apparently 

 frozen ; they were not brittle, and an at- 

 tempt to bend or break them resulted in a 

 very prompt but partial restoration of vi- 

 tality (or consciousness ?). Specimens thus 

 roughly handled were permanently injured 

 by being bent, even if not in excess of a de- I 



gree of curvature that they can and do 

 readily assume when in their normal con- 

 dition. On placing specimens freed from 

 mud in water of a temperature of 60° Fahr., 

 which is pretty nearly or quite that of the 

 ditch-water in summer, they only fully re- 

 vived after lying on their sides, at the bot- 

 tom of the vessel, for from twenty-five to 

 forty minutes, and seemed to be injured 

 permanently by the sudden change ; but, if 

 placed, with the mud still adhering to them, 

 in water at a temperature of 40° Fahr., 

 which became gradually warmer, by the ves- 

 sel containing the fish being removed to a 

 warm room, the minnows would become 

 wholly themselves again, in from ten to fif- 

 teen minutes, and swim off in full vigor, as 

 the mud slowly loosened from them and 

 settled to the bottom of the' vessel. As 

 taken from the bottom of the ditch, the mud 

 in which these minnows were hibernating 

 was of about the consistency of cheese. 

 As far as we were able to determine, these 

 fish had burrowed tail-foremost, to a depth 

 of from four to nine inches, and, in every 

 instance, we believe the tail was deeper than 

 the head, the position varying from almost 

 horizontal to nearly or quite perpendicular. 

 Pursuing the investigation somewhat 

 further, we found that, where these fishes 

 had gone into winter-quarters in deep water, 

 i. e., from three to five feet deep, the hi- 

 bernating slumber was not as profound ; 

 and, when they were placed in clear water, 

 at a temperature of 46° Fahr., they almost 

 immediately swam about; slowly at first, 

 but with steadily-increasing activity, and, 

 in from three to five minutes, were in full 

 possession of all their powers, and assumed 

 the statue-like positions common to them, 

 when seen in summer, when, for many min- 

 utes together, they will remain immovable, ^ 

 and only move when the near approach of 

 an insect larva offers them a sure chance 

 for a meal, or portion of one. It should be 

 here mentioned that the water in the ditches 

 from which we first gathered specimens va- 

 ried from nine to fifteen inches in depth, 

 and was coated with ice one inch thick. 



