FISHES III 



E. inconstans (Kirtland). Brook stickleback (Fig. 48). Length 

 65 mm.; head 3.5; depth 4; color of males in spring jet black, tinged 

 with red anteriorly; females olivaceous, mottled and dotted with black; 

 rays of dorsal fins IV-I, 10; anal I, 10: western New York to Kansas and 

 northward to Saskatchewan; in small streams; common. 



Subspecies of E. inconstans 



E. i. cayuga Jord. Size smaller; ventral plate U-shaped instead of 

 V-shaped; ventral spines as long as pubic bones: Ithaca and Syracuse, 

 N. Y. 



E. i. pygmcea (Agassiz) . Size small ; rays of dorsal fins III or IV-I, 

 6; anal I, 6: Lake Superior. 



3. P^ygosteus Brevoort. Body naked except for small bony plates 

 along the base of the median fins; free dorsal spines 9 to 11, diverging 

 right and left; pubic bones weak; gill membranes as in Eucalia: 2 species, 

 I of which, P. sinensis, in China. 



P. pungitius (L.). Ten-spined stickleback. Length 75 mm.; head 

 4; depth 5 or 6; color olivaceous, punctulate, irregularly barred with 

 darker; rays of dorsal fin VIII or IX-I, 9; anal I, 8: Atlantic coast of 

 America and Europe, from Long Island to the Arctic, ascending the 

 rivers; also in tributaries of the Great Lakes and northward to Alaska; 

 often very common. 



4. Apeltes Dekay. Body naked; back rather elevated; 3 strong free 

 dorsal spines; tail very slender; pubic bones weak, not joined in the 

 median line; gill membranes joined to isthmus: i species. 



A . quadracus (Mitchill) . Four-spined stickleback. Len gth 50 

 mm. ; head 4 ; depth 4 ; rays of dorsal fin III-I, 1 1 ; anal 1,8- colorbro wn- 

 ish olive above; silvery below; male almost black; body stout: Maine to 

 New Jersey, in salt water, often ascending the streams; very common 

 northward. 



Suborder 2. Salmopercae. — The trout perch. Adipose fin pres- 

 ent; ventral fins abdominal; dorsal, anal and ventral fins each with i or 2 

 spines; maxillary toothless and not forming the margin of the mouth; 

 scales ctenoid; head scaleless; pseudobranchise present: i family. 



Family Percopsidae. — Body elongate; caudal peduncle long and 

 slender; mouth small, horizontal; branchiostegals 6; tail forked; stomach 

 siphonal with 10 pyloric caeca: 2 genera. 



I. Percopsis Agassiz. Body slender, pellucid; dorsal fin with 2 

 feeble spines; anal with i: i species. 



P. guttatus Ag. Trout perch. Length 150 mm.; head 3.75; depth 

 4.3; color pale olivaceous, with a silvery stripe along the lateral line; 



