LAMPREYS AND FISHES OF INDIANA. 223 



Indiana line, in the vicinity of Chicago. Professor Kirsch (4, '94, 36) 

 reports having taken this fish at several points on Eel and Blue rivers, 

 in Northeastern Indiana. 



Order 7. ISOSPONDYLI. 



This order is based on characters which require careful dissections for 

 their determination. The most essential of these characters is the pos- 

 session of a precoracoid arch. From the Eventognathi th% order is dis- 

 tinguished by the fact that the lower pharyngeal bones are not enlarged, 

 and do not bear teeth fitted for triturating food. It is more difiicult to 

 distinguish the members of the group from those of the next order — the 

 Haplomi. An attempt to render aid in accomplishing this has been 

 made on page 170, to which the student is referred. 



ANALYSIS OF THE FAMILIES OF ISOSPONDYLI REPRESENTED IN INDIANA. 



A. Lateral margins of the upper jaw formed by the maxillaries. 

 a. No adipose fin present. , 



b. Lateral line developed ; conspicuous teeth on tongue. 



Hiodontidce, p. 223. 

 bb. No lateral line ; teeth feeble or wanting. 



Ciupeidce, p. 225. 

 aa. An adipose fin present. Salmonidce, p. 227. 



A A. Lateral margin of the upper jaw formed by the premaxillaries. 



Percopsidce, p. 233. 



Family HIODONTID.E. 



Body compressed, covered with cycloid silvery scales. Head scaleless. 

 Mouth large, oblique ; the margins formed by the maxillaries, a row of 

 teeth along the margin of the tongue, some of which are canine in form. 

 Feeble teeth on the maxillaries. Teeth on the vomers, palatines and 

 pterygoids. Eyes large. Gill rakers short, few. Lateral line present. 

 No adipose fin. 



Genus HIODON LeSueur. 



Generic characters included in the above. Two species are found 

 within our limits : 

 a. Developed dorsal rays, nine ; anal rays, thirty to thirty-two. 



alosoides, p. 224. 

 aa. Developed dorsal rays, eleven or twelve ; anal rays, twenty-eight. 



tergistis, p. 224. 



