April, 1910. Fishes of Chicago — Meek and Hildebraxd. 285 



Anguilla rostrata. (Le Sueur). American Eel; Fresh-water Eel. 



Head 7 or 8; depth 12 to 17; D. about 60. 



Body elongate, subcylindrical anteriorly, compressed posteriorly; 

 snout pointed, the maxillary reaching past orbit; lips thin; the lower 

 jaw the longer; gill membranes ven,'' broadly joined across isthmus, 

 the gill openings small; scales minute, oblong in oblique rows or 

 bunches each at right angles with the other; no ventrals; lateral line 

 complete. 



Length 3 to 4 feet. 



This eel inhabits the West Indies, and the larger streams of North 

 America east of the Rockies. 



Lake Michigan, Millers, Indiana; Lake Michigan, Pine, Indiana. 



Order ISOSpondyll. 



Herring, Shad, and Salmon. 



Skeleton bony; anterior vertebrae simple, without Weberian 

 ossicles; dorsal and anal fins without spines; ventral fins abdominal; 

 adipose fin present or absent; pectoral arch suspended from the skull; 

 mesocoracoid developed; opercle well developed ; maxillary distinct, 

 forming a part of margin of upper jaw ; gills 4, a slit behind the fourth. 



a. No adipose fin; belly behind ventrals, narrow, the scales not 

 passing over its median line. 



b. Lateral line present, well developed. Hiodontida, 285 

 bb. Lateral line absent. 



c. Last dorsal ray much produced; mouth small, subinferior. 

 toothless. Dorosomid<B, 287 



cc. Last dorsal ray not produced beyond the others; mouth large, 

 terminal. Clupeidce, 288 



aa. Adipose fin present ; belly rounded and covered with scales. 



SalmonidcB, 289 



Family Hiodontidfe. 



The Mooneyes. 



Body deep, much compressed, covered with silvery cycloid scales; 

 head naked ; jaws, vomer, palatines, and pterygoids with small cardi- 



