April, 1910. Fishes of Chicago — Meek and Hildebrand. 297 



Des Plaines River, Chicago, Illinois; Thorn Creek. Thornton, Illinois; 

 Calumet River, Clark, Indiana. 



Esox masquinongy Mitchill. Muskalonge. 



Head 3.6 to 4.0; depth 6; D. 17 to 18; A. 15 to 17; scales 150. 



Body elongate, compressed; mouth very large, maxillary reaching 

 past eye, its length 2 in head ; snout 2.2 ; diameter of eye 10.6 ; branch- 

 iostegals 17 or 18; lower half of cheeks and opercles without scales; 

 caudal fin forked. 



Color dark-gray, sides with round dark spots, the young with bars; 

 fins with black spots. 



Length 3 to 6 feet, reaching a weight of 100 pounds. 



This species inhabits the large lakes and streams of the Great 

 Lake region and Upper Mississippi Valley. 



Lake Michigan, Edgemoor, Indiana. 



Family I'liibrlclH*. 



The Mudfishes. 



Body elongate, subcylindrical anteriorly, compressed posteriorly; 

 head and body covered with cycloid scales; ventral fins abdominal; 

 dorsal fin posterior, above anal; mouth rather small, premaxillary 

 not protractile; lower jaw, vomer, and palatines with bands of villi- 

 form teeth; stomach without blind sac; air bladder simple, with 

 distinct duct; no lateral line. 



Genus Umbra (Kramer) Miiller. 



Body elongate, top of head flat, lateral line wanting; branchios- 

 tegals 6 to 8; gill rakers little developed; gill membranes little con- 

 nected ; lateral margin of the upper jaw formed by the maxillaries ; 

 supplemental maxillary absent. 



Umbra limi (Kirtland). Mud Minnow. 



Head 3.3 to 3.8; depth 3.9 to 5.3; D. 14 or 15; A. 8 or 9; scales 35. 



Body elongate; compressed posteriorly; head flat, covered with 

 scales, those on opercles large and imbedded; mouth rather large, the 

 maxillary reaching nearly to eye; interorbital space flat or flattish 

 4.3 to 5.4 in head; eye 3.8 to 5.2; snout 2.8 to 3.5; dorsal fin inserted 

 behind ventrals and on posterior half of body, its distance from tip 



