392 
BULLETIN OF THE BUREAU OF FISHERIES 
Pigmentation. — The marking consists of irregular mottling of brown, especially 
over head and dorsal aspect, becoming scarcer over sides. Ventral aspect and ventrals 
are colorless. The other fins are mottled. 
Family GASTEROSTEIDi^E, Sticklebacks 
59. Eucalia inconstans (Kirtland). Brook stickleback. 
RECORD OF CAPTURE 
The brook sticldeback, true to its name, was found in the many creeks tributary 
to Lake Erie and weed beds of the Niagara River, but never in the lake itself. 
DESCRIPTION 
The absence of lateral plates, only 5 or 6 dorsal spines, unkeeled tail, and rounded 
caudal are field characters which brand this stickleback immediately. 
19. 6 -millimeter stage . — Total length, 19.6; standard length, 17.1; length to vent, 
9.9; length of head, 5.4; greatest depth, 4.9; diameter of eye, 2.0 millimeters. Myo- 
meres, 11 to vent plus 18 behind. Dorsal IV-I, 10 (spines short, even in length); 
anal 1, 10 ; caudal rounded. Elongate body, but rather stout; caudal peduncle without 
a keel; smooth sldn without any lateral plates; ventral spines small. 
Pigmentation. — Chromatophores occur on both jaws, and thickly over top of 
head, so that the unpigmented pores are prominent on forepart of head. The chroma- 
tophores extend evenly and thickly down dorsal ridge and up over dorsal rays, 
evenly also on lateral aspect where they outline the myomeres. Some white patches of 
clear skin appear at intervals but not in a pattern. Ventral surface of head and 
stomach region is pale. 
BREEDING 
The brook stickleback is a nest-builder and defends its young with the utmost 
coinage. During the breeding season the males become jet black, tinged everywhere 
with vivid copper color. 
60. Gasterosteus aculeatus Linnaeus. Two-spined stickleback. 
RECORD OF CAPTURE 
A few young of this species were taken in weed beds of the Niagara River. They 
are of rare occurrence in the region. 
DESCRIPTION 
The two-spined stickleback is easily recognized by the single pair of large spines 
forming the first dorsal, implied by its name, the appearance of lateral plates, keeled 
caudal peduncle, and lunate caudal. 
16 .5 -millimeter stage . — Total length, 16.5; standard length, 14.5; length to vent, 
9.7; length of head, v 5.0; snout, 1.6; diameter of eye, 1.65; greatest depth, 3.8 milli- 
meters. Myomeres, 15 to vent plus 16+ behind. Dorsal II— I, 11; anal I, 9. Body 
fusiform; caudal peduncle short but very slender, distinctly keeled; bony plates on 
sides not yet evident in these young specimens. 
Pigmentation. — The body is greenish in tinge but not as deeply colored as older 
stages. Chromatophores are arranged thickly over top of head and in about 10 short 
