MANY-SPINED STICKLEBACK. : 999 
quarrelsome, and in default of other game they destroy each other. The 
males are more active than the females. In the breeding season the 
males become jet black. In the spring this species, as well as all the 
other species of Stickleback, builds a nest for its eggs, and defends this 
nest vigorously. | 
GENUS 88. PYGOSTEUS. Brevoort. 
Pygosteus (Brevoort, Mss.), GILL, Cat. Fishes East Coast, Proc. Ac. Nat. Sci., 186i (not 
characterized); Can. Nat., August, p. 8 (reprint), 1865. 
Gasterostea, SAUVAGE, Nouv. Archives du Mus., Paris, 1872. 
Type, Gasterosteus occidentalis, Cuv. and Val.=G. pungitius L. 
Etymology, puge, rump; osteon, bone. 
Body slender, elongate, somewhat compressed ; caudal peduncle very slender, with a 
strong keel on each side, which renders it much broader than deep; skin destitute of 
bony plates (except those connected with the pelvis); the plate extending upward from 
the ventral fins well developed, striated; head rather long; the mouth as in the other 
species; naked area in front of pectorals moderate; backward processes from the 
shoulder-girdle below well developed, widely divergent, forming a V shaped figure, em- 
bracing a large naked space; dorsal spines moderate, subequal, or the anterior ones 
rather highest ; spines not set in a right line, diverging alternately to the right and left, 
with more or less regularity ; spines 7 to 9 in number; anal spine similar to the others; 
innominate bones rather feeble, joined more or less completely on the middle line of the 
belly ; ventral spines moderate, finely toothed; gill:membranes free from the isthmus 
posteriorly. Perhaps but a single species widely distributed in northern regions, in both 
fresh and salt water. Tho group differs from Gasterosteus mainly in the increased num- 
ber of dorsal spines, and the greater freedom of the gill-membranes. It is probably un- 
worthy of retention as a distinct genus. 
165. Pygosrmus PuNnertivus (L.) Gill. 
Wany=spimed Stickleback. 
Gasterosteus pungitius, LINNZUS, Syst. Nat. 1753.—GUNTHER, Cat. Fish., i, 6, BEAN, Bull. 
U. S. Nat. Mus., xv, 1879, 129, and of most writers. 
Gasterosteus concinnus, RICHARDSON, Fauna Bor. Amer., 1836, 57.—GUNTHER, Cat. Fish., 
1 (Oh, i . 
Gasterosteus occidentalis, CUV. and VAL., Hist. des Poiss., iv, 1829, 509.—DrKay, New York 
Fauna Fishes, 68.—GUNTHER, i, 6. 
Pygosteus pungitius, GILL, Mss. 
Gasterosteus mainensis, STORER, Bost. Journ., i, 464.—GUNTHER, i, 6. 
Gasterosteus nebulosus, AGASSIZ, Lake Superior, 1850. 
Pygosteus nebulosus, JORDAN, Man. Vert., 1876. 
Pygosteus occidentalis, var. nebulosus, JORDAN, Man. Vert, Ed. 1, 260. 
Gasterosteus dekayi, AGASSIZ, Lake Superior, 1850, 311.—Sror#r, Hist. Fish. Mass. 
Gasterostea pungitia, occidentalis and blanchardi, SAUVAGE, Nouv. Archiv. Mus. Paris, 1873. 
Description.—Olivaceous above, profusely punctulate; sides irregularly barred with 
darker; belly silvery; body very slender, somewhat compressed, tapering into the very 
