310 REPOET OP COMMISSIONER OF FISH AND FISHERIES. 



11. Argyrosomus hoyi < rill. 



Moon-eye; Moon-eye Cisco; Cisco; Kieye; Chub. 



Argyrosomus hoyi (Cill ms.) Jordan, American Naturalist, ix, March, 1875, 135, Lake 

 Michigan, near Racine, Wis. 



Description. — Head, 4£; depth, 4£; eye, 4| to 4§; snout, 3f to 3f; 

 maxillary, 2| to 3 in head, reaching to vertical of middle of pupil. 

 B. 10; A. 11 or 12; scales, 8 or 9-73 to 80-7. Gillrakers, 14+25 or 

 20, slender, about 2 in eye. Vertebrae, 50; branchiostegals, 8 or 9. 

 Body rather elongate, compressed, £he back somewhat elevated. 

 Mouth rather large, subterminal, the lower jaw shorter than upper, 

 even when the mouth is open; tip of muzzle rather bluntly truncate, 

 somewhat as in a true Goregonus; mandible nearly reaching posterior 

 edge of eye, 2* in head. Ilead rather long, slender, and pointed. 

 Supraorbital and preorbital long and narrow. Distance from tip of 

 snout to occiput, 2i to 2-| in distance from occiput to origin of dorsal 

 fin; fins low; free margin of dorsal very oblique, the length of the 

 anterior rays If in head, that of the last ray less than half length of 

 the first; longest anal ray, 2f in head and more than twice as long as 

 the last ray. Pseudobranchke very large ; tongue with traces of teeth. 



Color light iridescent blue on back, scales with a few fine dark 

 punctulations reaching about two scales below lateral line; sides and 

 under parts rich silvery, brighter than in any other of our Goregonince, 

 much as in Hiodon and Albula; top of head light olivaceous; cheeks 

 silvery; dorsal, caudal, and pectorals with some dark on their margins; 

 anal and ventrals white, with some dark dustings; the male, perhaps, 

 a little richer, more iridescent blue on back, and with the scales a little 

 thicker and less closely imbricated. Length, 13 inches. Beep waters 

 of Lake Michigan; the smallest and handsomest of our Coregonince. 



The only specimens known until recently were the two sent to Br. 

 Gill and the one to Br. Jordan by Br. Hoy; but during recent investi- 

 gations by the Fish Commission this species was found to be one of 

 the principal fishes caught in the gill nets in the western part of Lake 

 Michigan. It is a true Argyrosomus, though approaching Goregonus. 



Table of comparative measurements of Hoy's whitejish {Argyrosomus hoyi). 



Thicker and less closely imbricated than in No. 57. 



