226 FISHES OF ILLINOIS 



length. Color of upper parts pale olive-buff, the scales with faint edg- 

 ings of black; 8 or 9 black spots on each side anterior to adipose fin and 

 above lateral line; a dusky median lateral band, more or less broken 

 into spots; lower portion of sides and belly silvery; entire fish trans- 

 lucent ; the cerebral membranes showing olive underneath skin of head ; 

 peritoneum silvery; cheeks, opercles, jaws, and chin silvery with em- 

 erald luster; iris silvery white with faint luster of rose; fins plain, trans- 

 parent. Head slender, conical, 3.2 to 3.7; width of head 1 . 8 to 2 in its 

 length ; interorbital space 3 . 5 to 4 in head ; eye . 9 to 1 . 2 in interorbital 

 space, 3.3 to 4. in head; nose 2.4 to 3; mouth moderate, subinferior, 

 maxillary short of orbit, 3 to 4 in head; lower jaw included. Dorsal I 

 (occasionally II), 9-11; the spine very weak, the fin inserted much nearer 

 muzzle than base of caudal, almost exactly over ventrals; caudal deeply 

 forked; anal I, 5-7 ; ventrals abdominal, nearer anal than angle of union 

 of gill-membranes; pectorals reaching past front of ventrals, 1.2 to 1.5 

 in head. Scales 6, 47-54, 7, ctenoid, being most distinctly so on caudal 

 peduncle; lateral line developed, nearly straight. 



This interesting and graceful little fish, a distinctly northern 

 species in its main range, has been found by us chiefly in clear spring 

 waters at various points along the Illinois River from Meredosia to 

 Hennepin. We have taken it also once from a small stream near 

 Lincoln, in Logan county, and once from Lake Michigan, off Chicago. 

 It is a wide-ranging species, known from the streams of New England 

 and Quebec, thence west to Kansas and northward to Hudson Bay 

 and the Saskatchewan Valley near Medicine Hat. It is common in 

 the Great Lakes, but rare south of them. 



It spawns in spring, and females greatly distended with eggs 

 were caught by us at Havana on the 10th of March. Surface says 

 that in Cayuga Lake, New York, females captured in May were in 

 ripe condition. 



Family ATHERINID^l 



(the silversides) " 



Body rather elongate, somewhat compressed ; scales generally cycli iid ; 

 head usually scaly; lateral line absent or represented by only a few rudi- 

 mentary tubes; skeleton osseous; anterior vertebra? simple; ventral fins 

 abdominal; two dorsal fins, well separated, the first consisting of 3 to 8 

 slender flexible spines, and the second of soft rays; anal with a weak 

 spine; no mesocoracoid; gill-membranes not connected, free from isth- 

 mus; branchiostegals 5 or 6; pseudobranchias present; gill-rakers usu- 

 ally long and slender; opercular bones without spines or serrature; pre- 

 maxillaries protractile or not; teeth usually present on jaws, sometimes 

 on vomer and palatines ; no pyloric caeca ; air-bladder present . 



