350 CONTEIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



*' Pectorals narrow, with few ( 12-15) rays ; ventral rays 6 ; scales moderate . Usibra, 165. 

 ** Pectorals broad, with many (3;V36) rays; ventral rays 3 ; scales small.. Dalli a, 166. 



165.— UMBKA Miiller. 



Mud-fislies. 



(Melamira Agassiz.) 



(Kramer; Miiller, Ahhandl. Akad. Wiss. Wien, Bcrl. 1842, 188: type JJrnbra erameri 

 Miiller. ) 



Body oblong, covered with cycloid scales of moderate size, without 

 radiating striae ; no lateral line. Head shortish, little depressed. Eye 

 rather small. Cleft of mouth moderate. Ventral fins 6-rayed, below 

 or slightly in front of dorsal 5 anal fin much shorter than dorsal. Pec- 

 torals rather narrow, rounded, placed low, with 12-15 rays, which are 

 much jointed. Caudal rounded. Preopercle and preorbital with mu- 

 cous pores. Branchiostegals 6. GiU-rakers short, thick. Size small. 

 Two species, very similar to each other, inhabiting the waters of the 

 United States and Austria. (Latin, umbra, a shade.) 



571. U. limi (Kirt.) Gthr. — Mud Minnoto ; Dog-fish. 



Dark-green or olive, mottled, sides with irregular narrow pale bars, 

 these often obscure or wanting ; a distinct black bar at base of caudal ; 

 whitish stripes sometimes present along the rows of scales. Head 3'^ 

 in length; depth 4^ B. 6; P. 14; D. 14; A. 8; V. C; Lat. l. 35; L. 

 transv. 15. L. 4 inches. Vermont to Minnesota and South Carolina. 

 Abundant northward in weedy streams and ditches. " A locality which 

 with the water perfectly clear will appear destitute of fish will perhaps 

 yield a number of mud-fish on stirring up the mud at the bottom and 

 drawing a seine through it. Ditches in the prairies of Wisconsin, or 

 mere bog-holes, apparently afibrding lodgment to nothing beyond tad- 

 poles, may thus be found filled with 3Ielanurasy (Baird.) 



{Hjidrargyra limi Kirtland, Bost. Jonm. Nat. Hist, iii, 277 : Melamira anniilata Ag. 

 Am. Joiu'u. Sci. & Arts, 1854, 135 : Umbra limi Giinther, vi, 232 : Leuciscus pygmceus De 

 Kay, New York Fauna, Fishes, 214 : Umbra irygmwa J ovdau, Bull. U. S. Nat. Mus. x, 53 ; 

 the eastern form, pygmcea, usually slightly diiferiug in proportions.) 



166.— DAJLL.IA Bean. 



(Bean, Proc. U. S. Nat. Mus. 1879, 358: type Dallia pectoralis Bean.) 



Body oblong, covered with small, partly embedded cycloid scales; a 

 trace of lateral line; a line of mucous tubes below eye. Eye small. 

 Cleft of mouth moderate. Villiform or almost cardiform teeth on jaws, 

 vomer, and palatines; those on premaxillaries enlarged. Ventrals in 



