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



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

 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 Uiiibridje. 



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) Mtiller. 



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 n'early to eye; interorbital space flat or flatfish 

 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 



