226 FISHES OP ILLINOIS 



parts pale olive-buff, the scales with faint edgings 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 translucent; the cerebral membranes showing 

 olive underneath skin of head; peritoneum silvery; cheeks, opercles, jaws, 

 and chin silvery with emerald luster; iris silvery white with faint luster of 

 rose; fins plain, transparent. 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, sub- 

 inferior, 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. 

 Scale 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> 



THE SILVERSIDES 



Body rather elongate, somewhat compressed; scales generally cycloid; 

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

 mentary tubes; skeleton osseous; anterior vertebras 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 isthmus; branchi- 

 ostegals 5 or 6; pseudobranchise present; gill-rakers usually long and slender; 

 opercular bones without spines or serrature; premaxillaries protractile or 

 not; teeth usually present on jaws, sometimes on vomer and palatines; no 

 pyloric casca; air-bladder present. 



