SIXTY-TWO SPECIES OF FISHES FROM LAKE ERIE 
357 
Dorsal about 10, incompletely formed; anal about 9, incompletely formed; marginal 
fin fold gone; caudal fully rounded, as adult; pectorals large, rays reaching to ventrals; 
ventrals budding shortly before vent. Differs from preceding stage in comparatively 
smaller eye longer snout, more superior mouth, longer lower jaw. 
Pigmentation. — Chromatophores have increased in number so that the body is 
quite evenly covered with stellate chromatophores, except beneath the stomach. 
Dorsal, anal, and pectorals have chromatophores arranged along rays, similar to 
caudal. 
BREEDING 
The barred killifish apparently breeds in June locally. No data are available 
concerning the duration of the breeding season, but in the Chesapeake Bay region 
it is reported to spawn from April until September. At mating time the males are 
olive-colored with about 20 pearly-white or silvery crossbars. ' 
Family PERSQP3ID7E, Trout-perches 
36. Percopsis omiscomaycus (Walbaum). Trout-perch. 
RECORD OF CAPTURE 
Although young ranging from 6 to 35 millimeters were taken frequently at the 
eastern end of the lake from June 12 to August 10, 1928, usually near shore in water 
Figure 76 .— Percopsis omiscomaycus, immediately after hatching, 6 millimeters 
less than 20 meters deep, only a few under 8.4 millimeters were taken during 1929, 
on one occasion near F airport, Ohio, on July 12, and again off Rondeau, Ontario, 
on the following day. At the western extremity of the lake, however, in 1929 a 
ripe female was taken on May 6 and eggs of this species were abundant in the tow 
on that date and at intervals until June 7. The only larva was taken in this region 
on June 29. It measured 6.5 millimeters. The trout-perch is one of the commonest 
Lake Erie species, being distributed in rather deep water except during the breeding 
season. 
DESCRIPTION 
The large head, deep short body, and especially the small number of myomeres 
(13 plus 15) make the young of this species easily distinguishable from others. 
Eggs . — Freshly spawned eggs measured 1.36 to 1.85 millimeters, and contained 
much oil distributed in numerous globules in unfertilized specimens, but usually 
mingled into one large globule up to 0.7 millimeters in diameter after fertilization. 
Newly hatched larva : — Total length, 6.0; length to vent, 3.0; greatest depth, 1.1; 
diameter of eye, 0.5 millimeters. Myomeres, 13 to vent plus 21 behind. Charac- 
terized by much-prolonged, pointed snout, with rather small, inferior mouth; 
small, oval eye much lower than in adult, and later developmental stages showing 
a gradual movement upward; snout about equal to eye. Embryonic marginal fin 
