630 



TELEOSTEI 



gials. Pelvic bones usually connected with scapular arch. 

 Ventral fins with one spine and one or two soft rays. 



...sc. 



..pi. 



FIG. 383. Pectoral arch (left side) of Gastrosteus aculeatus. (After Parker.) 

 cl, Clavicle ; cm; coracoid ; pt, pterygials ; sc, scapula ; scl, supra-clavicle. 



Four genera : Gastrosteus, Apeltes, Eucalia, Spinachia. 



The little Three-spined and Two-spined Sticklebacks (Gastro- 

 steus aculeatus and G. pungitius), which include many varieties that 

 have been regarded as distinct species, are among the best known 

 of our British Fishes. They are remarkable for the perfect indiffer- 

 ence with which they can be transported from fresh into salt water, 

 and vice versa, and for the elaborate nests which the males build 



FIG. 384. Gastrosteus aculeatus. x 1. (After Goode. ) 



in fresh or brackish water, and over which they watch with the 

 greatest vigilance after the female has deposited her relatively 

 large eggs. 1 These nests are made of weeds and twigs fastened 

 together by threads secreted by the kidneys of the male. The 



1 On the nesting habits, cf. Coste, Mim. Acad. Sci. Paris, x. 1848, p. 575, PI. ; 

 Warington, Ann. Mag. Nat. Hist. (2) x. 1852, p. 276 ; Prince, Ann. Mag. Nat. 

 Hist. (5) xvi. 1885, p. 487, PI. xiv. On the spinning organ : Mo'bius, Arch, Mikr. 

 Anat. xxv. 1886, p. 554, PI. xxii. 



