998 - FISHES—GASTEROSTEID A. 
Smooth-skinned Sticklebacks with the caudal keel undeveloped ; the dorsal spines in 
small number and placed vertically in a right line; the spines all unserrated; ventral 
plates coalesced into a narrow plate on the median line between the ventral fins; a dis- 
tinct subquadrate post-pectoral plate; caudal peduncle comparatively short and stout ; 
gill-membranes posteriorly free from the isthmus. 3 
Small fishes inhabiting the inland brooks and Jakes of the Northern United States. 
Bat one species is certainly known, running into two or three varieties. This group is 
probably unworthy of generic distinction from Gasterostcus, from which it differs mainly 
in its feeble spines, and lack of armature, and in the freedom of the gill-membranes 
from the isthmus. 
164. EKucauia 1nconsTANs (Kirtland) Jordan. 
Brook Stickleback. 
Gasterosteus inconstans, KIRTLAND, Bost. Journ. Nat. Hist., 1839; SToRER, Synopsis, 1846. 
—CopE, Proc. Ac. Nat. Se. Phila , 186. 
Apeltis inconstans, JORDAN, Ind. Geol. Surv., 1874, 1875, 217. 
Eucalia inconstans, JORDAN, Man. Vert, 1876, 248; Proc. Ac. Nat. Sc. Phila., 1877, 65; 
Man. Vert., Ed. 1, 1878, 259.—NELSoN, Bull. Ills. Nat. Hist. Soc., 1876 —JORDAN and 
COPELAND, Check List, 1876. 
Gasterosteus micropus, COPE, Proc. Ac. Nat. Sai. Phila., 1864, 186. 
var. pygmea. 
Gasterosteus pygmeus, AGASSIZ, Lake Superior, 1850. 
Hucalia inconstans var. pygmea, JORDAN, Man. Vert., 1876, 248; Proc. Ac. Nat. Se. Phila,, 
1877, 66.—Man. Vert., Ed. 2d, 1878, 259. 
var. cayuga. 
Kucalia inconstans var. cayuga, JORDAN, Man. Vert., Ed. Ist, 1876, 249; Proc. Ac Nat. Se. 
Phila., 1877, 66; Man. Vert., Ed. 2d, 1878, 259. 
Description —Males in spring jet black, tinged anteriorly with coppery red; females 
and young olivaceous, mottled and dotted with black; body moderately elongate, little 
compressed, the caudal peduncle comparatively stout, not keeled ; skin smooth, entirely 
destitute of dermal plates, the skeletal plates covered by it; innominate bones small, 
lanceolate, covered by the skin; area in front of pectorals small ; thoracic processes very 
slender and widely separated, covered by skin; gill: membranes somewhat free from the 
isthmus posteriorly ; gill rakers short ; dorsal spines low, subequal, in a right line, those 
in front lowest, a cartilaginous ridge along their base; ventral spines short and sharp, 
serrated; head 34; depth 4; D. IV-I, 10; A. I, 10. Length 24 inches. 
Habitat, sluggish, grassy brooks, from central Ohio, northern Illinois and Kansas 
northward ; very abundant in the tributaries of the Great Lakes. 
Habits. —This interesting little fish is very abundant in many streams 
in the northern part of Ohio. It frequents small brooks, lurking among 
the weeds and grass, ready to dart on any luckless minnow or insect that 
attracts its notice. In the aquarium these Sticklebacks are excessively 
