12 PROCEEDINGS OF THE ACADEMY OF [1885. 



ON THE AMERICAN 8PECIE8 OF THE GENUS UMBRA. 

 BY WILLIS 8. BLATCHLEY. 



I have compared numerous specimens of mud-minnows (Umbra 

 Miiller), from different parts of the United States, with a view of 

 ascertaining whether more than one species exists in our waters. 

 I find, as already noted by Jordan and Bean, two types ; the one 

 (limi) inhabiting the waters of the great lake region and north- 

 westwardly ; the other (pygrtidea), inhabiting the coastwise 

 streams from Connecticut to North Carolina. 



On careful comparison, the only constant difference between 

 these forms, which I am able to appreciate, is the coloration. 



The true Umbra limi is dull olive-green in color, with about 

 fourteen narrow, pale, transverse stripes, often obscure in the 

 young ; dark bar at base of caudal much less distinct, and lower 

 jaw always paler than in pygmaea. 



The eastern form, which I regard as a geographical subspecies 

 ( Umbra limi pygmaea), is much darker in color, with about twelve 

 pale, narrow longitudinal instead of transverse stripes, the one 

 beginning at upper angle of opercle being double the width of the 

 others ; dark bar at base of caudal very distinct, extending over 

 l£ scales ; lower jaw dark, almost black in adults. 



The following is the synonymy of each of the two forms : — 



Umbra limi. 



Hydrargyra limi Kirtland, Bost. Journ. Nat. Hist., iii, 1840, 277 

 (Northern Ohio). 



Melanura limi Agassiz, Amer. Journ. Sci. Arts, 1855, 217 ; Packard & 

 Putnam, Amer. Nat., Jan., 1872 (Mammoth Cave); Jordan, Man. 

 Vert., 1st ed., 1876, 253, 2d ed., 1878, and 3d ed., 1880, 265 ; Jordan, 

 Rept. Geol. Surv. Ind., 1875, 33 ; Jordan & Copeland, Check List 

 Fresh Wat. Fish. N. A., 1877, 143; Jordan, Bull. U. S. Nat. Mus., 

 ix, 1877, 49 (Ohio Valley); Jordan, Annals N. Y. Acad. Sci., i, 1877, 

 \... 4, 103 (Suamico R., Fox R., Rock R., Wisconsin R., White R.); 

 Nelson, Bull. 111. Lab. Nat. Hist., i, 43 ; Jordan, Bull. 111. Lab. Nat. 

 Hist., ii, 1878, 52 (Johnson and Union Counties, Illinois; Crystal 

 Lake, McHenry Co., 111.); Jordan & Brayton, Bull. U. S. Nat. Mus., 

 xii. L878, 84 (Ohio and 111. R. Basins) ; Forbes, Bull. 111. Lab. Nat. 

 Hist., ii. 1878, 7H (Food of Melanura limi). 



Umbra limi Giinther, Cat. Fish. Brit. Mus., vi, 1866, 232; Jordan, 

 Proc. Acad. Nat. Sci. Philad., 1877, 44 (Lakes, Laporte Co., Ind.; 



