(49) 

 The following table shows the position of the vent in 26 specimens. 



Length of 

 Fish in Inches. 



Position of Vent. 



No other conclusion seems possible from the above except that the vent 

 moves forward as the fish grows older, by the lengthening of the horizontal 

 part of the intestine or "rectum" of the fish. Sternotremia isolepis is the 

 young, Sternotremia mesotrema the half-grown and AjyJiododcinis cooJdamis 

 the adult of one and the same fish. 



Aphododerus isolepis occurs in sluggish waters and bayous throughout 

 the state. I have seen specimens from Calumet River, from numerous 

 streams and sloughs in the southern part of the state and from the Wabash 

 River at Mount Carmei, — the latter'collected at different times by Robert 

 Ridgway and Robert Kennicott. Union and Johnson counties. 



