630 TELEOSTEI CHAP: 
gials. Pelvic bones usually connected with scapular arch. 
Ventral fins with one spine and one or two soft rays. 
Fia. 383.—Pectoral arch (left side) of Gastrostews aculeatus. (After Parker.) 
cl, Clavicle ; cor, coracoid ; pt, pterygials ; sc, scapula ; sc/, supra-clavicle. ° 
Four genera: Gastrosteus, Apeltes, Hucalia, Spinachia. 
The little Three-spined and ‘T'wo-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 
Fia. 384.—Gastrosteus aculeatus. x1. (After Goode.) 
in fresh or brackish water, and over which they watch with the 
greatest vigilance after the female has deposited her relatively 
large egos.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, ef. Coste, Mém. Acad. Sci. Paris, x. 1848, ps 575, Pl. ; 
Warington, Ann. Mag. Nat. Hist. (2) x. 1852, p. 276; Prince, Ann. Mag. Nat. 
Hist. (5) xvi. 1885, p. 487, Pl. xiv. On the spinning organ: Mobius, Arch. Mikr. 
Anat. xxv. 1886, p. 554, Pl. xxii. 
