THE FAMILY OF THE SCADS, OR HORSE-MACKERELS 319 



the back, silvery on the sides and belly. The tail is forked. 

 The greatest length attained is 20 inches. 



Habitat. This fish is found almost all over the world, 

 extending from the Mediterranean northwards to Denmark, 

 southwards to the Cape of Good Hope, and found also in 

 China, Australia, and Chili ; it appears to be absent from the 

 w r estern shores of the Atlantic. In Britain and Ireland it is 

 found all round the coasts, but becomes scarce in the extreme 

 north. In food and habits it closely resembles the mackerel. 



Breeding. The fertilised eggs have not been obtained and 

 examined. In May, 1894, Mr. Holt obtained at Grimsby some 

 apparently ripe females from the North Sea, but they had been 

 caught the day before he received them. The eggs were quite 

 transparent, and floated in water at Cleethorpes, which was 

 not so salt as that of the sea. In breadth they were ro3 to 

 i -09 mm. or ^ inch. There was either a single oil globule or 

 two or three which united afterwards. The yolk was divided 

 throughout its substance into large masses, and it was remark- 

 able that these projected at the surface, so that the surface of 

 the yolk was not smooth and even as it usually is. Artificial 

 fertilisation was not successful, and the eggs did not live in 

 sea-water more than forty-eight hours. It seems very probable 

 that the peculiarities of these eggs, different from any known 

 in others, are due partly to the fact that they were not perfectly 

 ripe, partly to the fact that the females from which they came 

 had been dead for twenty-four hours. It will probably be found 

 that the eggs of the scad when fertilised are like those which 

 are believed on good evidence to belong to the American blue- 

 fish, and that the yolk-masses, as described by Mr. Holt, simply 

 show an unnatural or imperfectly developed condition of the 

 outer layer, of yolk segments which is natural in the fertilised 

 eggs. 



Although I have not examined the eggs at Plymouth, I have 

 obtained the young in the tow-net at the surface in August and 

 September. I took four specimens in all, from I inch to 2 inches 

 in length, from two to five miles off the coast. These were fish 

 which had passed through their transformations and developed 

 the characters of the fully developed scad ; and as spawning 

 appears to take place in -May and June their age may be 

 reckoned at from two to four months. 



