Jordan and Evermann. Fishes of North America. 743 



not; gill rakers moderate or rather long. Opercles unarmed. Skin 

 naked or with vertically oblong bony plates ; no true scales. Dorsal fin 

 preceded by two or more free spines; anal similar to soft dorsal, with a 

 single spine ; ventral fins subabdominal, consisting of a stout spine and 

 one or two rudimentary rays. Middle or sides of belly shielded by the 

 pubic bones. Pectorals rather short, unusually far behind the gill open- 

 ings, preceded by a quadrate naked area, which is covered with shining 

 skin. Caudal fin narrow, usually lunate. Air bladder simple; a few 

 pyloric coeca. Vertebrae 30 to 35; anterior vertebrae little enlarged. 

 Genera 5 ; species about 12. Small fishes inhabiting the fresh waters 

 and arms of the sea in Northern Europe and America ; noted for their 

 pugnacity. They are exceedingly destructive to the spawn and fry of 

 larger fishes. " It is scarcely to be conceived what damage these little 

 fishes do, and how greatly detrimental they are to the increase of all the 

 fishes among which they live, for it is with the utmost industry, sagacity, 

 and greediness that they seek out and destroy all the young fry that 

 come their way." (Giinther.) Most of the sticklebacks build elaborate 

 nests which the male fish defends with much spirit. The species are 

 extremely variable, being apparently readily affected by changes in 

 surroundings. (Gasterosteidw, Giinther, Cat., I, 1-7, 1859.) 



GASTEROSTEIN.B : * 



a. Pubic bones fully joined, forming a triangular or lanceolate plate on median line of 



belly behind and between the ventral fins. 

 1. Snout moderately produced, not tubiform ; caudal peduncle moderate ; ventral not 



far behind pectoral, its rays I, 1. 

 c. Gill openings confluent, the gill membranes forming a broad free margin across 



the isthmus. 



d. Dorsal spines 4 or 5, nondivergent, and nearly equally reclinable ; skin 

 naked ; tail not keeled. EUCALIA, 336. 



dd. Dorsal spines 8 to 11, divergent ; skin naked or nearly so ; tail keeled. 



PYGOSTEUS, 337. 



cc. Gill openings restricted, the membranes mesially united to the isthmus ; dorsal 

 with two free spines ; skin mailed, partly mailed, or naked. 



GASTEKOSTEUS, 338. 

 APELTIN^E : 

 aa. Pubic bones widely separated posteriorly, forming a bony ridge on each side of abdomen, 



between which are the ventral fins ; snout short. 

 e. Dorsal with four divergent spines ; sides not mailed. APELTES, 339. 



336. EUCALIA, Jordan. 



Eucalia, JOBDAN, Man. Vert., Ed. i, 248, 1876, (inconslans). 



Fresh-water sticklebacks, feebly armed, the skin not mailed, the dorsal 

 spines few and nondivergent, the gill membranes forming a free fold 

 across the isthmus ; pubic bones fully united. One species known, 

 (ei-, well; KaAid, nest, the species building nests, like other sticklebacks.) 



* The subfamily Spinachiinse, with the snout much produced, subtubiform, the dorsal spines 

 about 15 and the pubic bones joined only at base, consists of the European species, Spinachia 

 spinachia (Linnajus). It is not rare in Northern Europe and has been once (probably by error 

 in labeling) ascribed to Newfoundland. See Sauvage, Kevision des Epinoches, 1874, 36. 



