NOTROPIS 141 



orbit; lower jaw slightly shorter than upper; isthmus less than pupil. Teeth 

 1, 4-4, 1; intestine about 1.15 times length of head and body; peritoneum a 

 very dark brown to almost solid black. Dorsal fin with 8 rays, inserted a 

 little behind ventrals, about equidistant between muzzle and base of caudal; 

 longest dorsal ray usually a little less than head, 1 to 1.2; anal rays 8 (occa- 

 sionally 7); pectorals % to % to ventrals, 1.1 to 1.3 in head; ventrals to 

 vent, not reaching anal in any of our specimens. Scales 5 or 6 (usually 5), 

 35-37, 3; 13 to 15 in front of dorsal fin; lateral line complete, somewhat 

 decurved anteriorly. 



FIG. 35 



This species, rather rare in Illinois, is closely limited in the 

 main to the tributaries of the Wabash in the eastern part of the 

 state, from which it is recorded in our collections at 17 localities, 

 the only other places of its occurrence in this state being Cedar 

 Lake, in northeastern Illinois, Mazon creek, a branch of the 

 Illinois River near its origin, and a small bluff stream of the 

 Mississippi, in Hancock county. Its general range is from the 

 Lake Erie basin and the Ohio River westward to Arkansas and 

 Missouri. 



Females with fully developed eggs, and breeding males with 

 muzzle and chin tuberculate, have been taken by us in the latter 

 part of May. 



NOTROPIS HUDSONIUS (DEWiTT CLINTON) 



SPOT-TAILED MINNOW 



(MAP XXXVIII) 



DeWitt Clinton, 1824, Ann. Lye. Nat. Hist. N. Y., I, 49 (Clupea). 

 G., VII, 251 (Leuciscus); M. V., 57; J. & E., I, 269; N., 46 (Hybopsis); J., 56 (Al- 

 burnops); F. F., I. 6, 82 (Hybopsis); F., 77; L,., 17. 



The usually large and conspicuous black caudal spot of this minnow, 

 rarely absent in western specimens of the species, will commonly serve to 

 call attention to it when found, and will serve to separate it from the other 

 larger and paler species of Illinois Cyprinidce. Length 4 to 6 inches; body 

 moderately robust, not much elongate, considerably compressed, the sides 

 vertical at their middle; depth 4 to 4.5 in length; caudal peduncle shorter 

 than head, its depth 1.9 to 2.3 in its length. Color very pale olive; sides 



