STICKLEBACKS. 403 



and from the weather-side. In the daytime they avoid a ship, flying away from 

 it ; but, during the night, when they are unable to see, they frequently fly against 

 the weather-board, where they are caught by the current of air, and may be thus 

 carried to a height of some twenty feet above the surface of the water." In the 

 second account, which was published many years ago in Land and Water, the 

 author writes that in calm weather flying-Ash " are capable of clearing three 

 hundred yards. Their flight is frequently extended to double the distance by 

 .simply skimming the surface, as a swallow does a pool, and without disappearing. 

 I have observed that they never touch the surface more than twice consecutively, 

 though they may resume their flight after a period of complete immersion ; while 

 still in the air, they readily change their course to right angles with their first 

 line of flight, or even completely reverse it towards the point from which they 

 originally started. I have watched them for hours through a powerful double 

 glass, as they rose from either side of the bows of the ship, and noticed that the 

 pectoral fins are moved with a slight but very rapid quivering motion, which, I 

 have no doubt, assists to sustain them in the air. In rough weather the flight of 

 the flying-fish is more rapid, much higher, and of shorter duration than when light 

 winds prevail." This account confirms my own observations as to there being a 

 vibratory motion of the pectoral fins when first leaving the water, although the 

 writer is probably incorrect in his supposition that this assists the flight. 



Sticklebacks, Flute-Mouths, and Trumpet-Fish, — Families Gastrosteid.e, 



AULOSTOMATID+E, and CENTRISCID^E. 



Although the third of the above-named families is regarded by Dr. Giinther 



as forming a group apart, we may follow Day in placing the whole three in a 



single section, characterised by the spinous dorsal fin, when present, being either 



short or formed of isolated spines, and by the generally abdominal position of the 



pelvic fins, which in some instances are imperfectly developed. 



Familiar to every home-born Englishman as the fish upon which, 

 Sticklebacks . 



in common with minnows, he made his first experiment in angling 



with the aid of a bit of twine, a bent pin, and a worm, the sticklebacks have the 

 honour not only of representing a genus (Gastrosteus), but likewise a family by 

 themselves. Taking their name from the presence of a variable number of isolated 

 spines in advance of the soft dorsal fin, sticklebacks have the body more or less 

 elongate and compressed, the cleft of the mouth oblique, and the teeth villiform. 

 The gill-cover is unarmed, and the cheek covered by the infraorbital bone; and 

 in place of scales there are generally large plates along the sides of the body. The 

 pelvic fins, although abdominal in position, are connected with the pectoral girdle 

 by means of the pelvic bones, and consist of but one spine and a single ray: and 

 there are but three branchiostegal rays. Confined to the Temperate and Arctic 

 zones of the Northern Hemisphere, where they are represented by some half-score 

 species of small bodily size, sticklebacks arc mainly fresh-water fishes, although the 

 sea-stickleback (G. spinachia) is a marine or brackish-water form, and all the 

 rest can live as well in salt as in fresh-water. The British fresh-water repre- 

 sentatives of the genus are distinguished by the number of the dorsal spines, and 



