Jordan and E^'ermaiin. — Fts/ics of North America. 623 



teeth on premaxillaries, lower jaw, vomer, and palatines ; promaxillaries 

 not jnotractile ; lateral margin of npper jaw formed by the broad, short 

 maxillaries, which are toothless and without distinct supplemental bone; 

 lower jaw the longer. Gill openings wide, the membranes scarcely con- 

 nected ; gill rakers little developed ; branchiostegals 6 to 8. Scales 

 moderate, cycloid, covering head and body ; lateral line wanting. Dor- 

 sal fin moderate, posterior, in advance of anal ; veutrals small, close to 

 anal ; pectorals iuserted low ; caudal fin rounded. Stomach without 

 blind sac; no pyloric cteca ; pseudobrauchiai hidden, glandular; air 

 bladder simple. Oviiiarous fishes, the sexes similar. Carnivorous fishes 

 of small size, living in mud or among weeds at the bottom of clear, slug- 

 gish streams and ponds; extremely tenacious of life, like the Pwciliidw. 

 One genus with 3 species, {Umbra crameri of Austria,, and the following). 

 The family is near to the Luciidw, differing mainly in the smaller mouth 

 and weaker teeth. Like DaUia, Percopsis, Apliredoderioi, Cltoloyaster, and 

 other associated American fresh-water forms, Umbra must be regarded as 

 an archaic type, characteristic of some earlier fish-fauna. ( UinbridWy 

 Giinther, Cat., vi, 231, 232, 1866.) 



298. UMBRA (Kramer) Miiller 

 (Mudfishes.) 



Vmbrii, Kkamer, Auim. Austr. lufer., 1756; Muller, Abhandl. Akad. Wiss. Wien. Berl., 188, 



1842, (crameri). 

 Melanura, Agassiz, Amer. Jouru. Sci. Arts, 1854, 135, (imuiilala, etc., —pygmsea). 



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

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

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

 slightly in front of dorsal ; anal fin much shorter than dorsal ; pectorals 

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

 much articulated ; caudal rounded., Preopercle and preorbital with 

 mucous pores. Branchiostegals 6. Gill rakers short, thick. Size small. 

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

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

 Melanuua (/ueAas, black; ovpa, tail): 

 a. Base of caudal with a dark bar; American species. 



6. Body with pale crossbars ; coloration dull olive green, with about 14 narrow, pale, 

 transverse stripes; dark bar at base of caudal often faint; lower jaw pale. 



LtMI, 919. 



bb. Body with lengthwise streaks ; coloration dark olive green, with about 12 pale narrow 



lengthwise streaks, the one at upper angle of operclu twice width of the others ; 



dark caudal bar very distinct ; lower jaw black. pygm^sa, 920. 



Subgenus MELANURA, Agassiz. 



919. UMBRA LIMI (Kirtland). 



(Mud Minnow ; Dogfish.) 



Head 3f ; depth 4i. B. 6; P. 14; D. 14; A. 8; V. 6; scales 35-15. 

 Body oblong, compressed. Coloration dull olive green, mottled with 

 darker and with about 14 narrow, pale, transverse bars, often obscure in 



