298 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



The Umbrids or mud minnows are a feeble family represented by 

 a single genus whose species are distributed in a notable manner. 

 A single one (Umbra unihra or kramcri) occurs in central and 

 southeastern Europe, Hungary and the neighboring countries, and 

 two others are inhabitants of the eastern slope of the American con- 

 tinent and the Mississippi valley, while all the intervening countries 

 are deprived of them. They are scarcely distinct from the pikes 

 and, as in them, the supramaxillaries form the lateral margins 

 of the mouth, but the jaws are not produced and the teeth are all 

 small and " villiform." In appearance, indeed, they are much more 

 like Cyprinodonts (killiefishes) than pikes. The species chiefly fre- 

 quent still waters and are most at home in muddy and reedy ponds 

 or in clear ponds with a muddy bottom ; they are also prone to resort 

 to sequestered pools or caverns. They hide on or rather in the 

 bottom, and where not one may be seen at first, numbers may be 

 secured by drawing a net over the bottom and stirring up the mud. 

 They are very tenacious of life and individuals have been kept by 

 the writer for many months without change of water in moderate 

 sized jars with water plants. Their behavior and carriage are char- 

 acteristic and have been especially described by a number of nat- 

 uralists, especially by Heckel and Kner (1858), C. C. Abbott (1884), 

 and L. Kathariner (1899). 



Ill 



From authors already cited and from personal observations a 

 tolerable biography may be obtained and the tale is of considerable 

 interest. 



In a clear pool some may be seen, if quietly approached, in mid- 

 water, perfectly motionless, with the pectoral fins closed and stretched 

 out and downward, at right angles to the trunk, and with the tips 

 curved slightly forward, while all the other fins (including the 

 ventral) are widely expanded; so they may remain for minutes at a 

 time or with a slight movement of dorsal rays ; then one pectoral may 

 be expanded and its surface displayed forward and backward while 

 the other fin may be appressed to the side. Another attitude often 

 assumed is one of balancing in midwater, when sometimes a vertical 

 position is taken, or even the back is inclined downward; the pec- 

 torals are then the principal fins used and are constantly moving in 

 an undulatory manner, the fully expanded ones being for a moment 

 outspread and horizontal to the length. Still another frequently 

 assumed attitude is a " statue-like " one which has been also desig- 

 nated by Abbott as the " salamandrine position," and which is often 

 maintained for several minutes at a time. " The body is frequently 



