198 LOWER VERTEBRATES. 



given to a scombrid, intermediate to some extent between the true mackerels, 

 Scomber, and the bonitos. The body is much stouter, but the spinous dorsal is short 

 and distant from the second as in Scomber/ the pinnules are more numerous, there 

 being eight above and seven below ; the teeth are very small, and the vomer and 

 palatines are destitute of any ; the corselet is much more developed than in Scomber; 

 the back is blue, and the belly silvery. The species attain a size of from about twelve 

 to sixteen inches, and a weight of three quarters of a pound to a pound and a half or 

 more. Auxis thazard is the scientific name of this species. 



Its range is chiefly in the tropical Atlantic, but it is quite erratic in its movements, 

 and frequently ascends far northward. It is only within a few years, "however, that 

 it has been observed along the eastern coast of the United States. They associate 

 together in large schools, — sometimes in immense numbers, — and, in the words of 

 one very practical observer, as many as one thousand barrels would be obtainable from 

 a school. There are, it is to be added, about eighty to one hundred to a barrel. It 

 was noticed, on one occasion, that a day after the appearance of this fish, the common 

 mackerel disappeared, but, whether the latter were driven away by them, or not, 

 was not determined. They feed on the so-called mackerel food. " They are very 

 easy to catch, flip like menhaden, do not rush, and are not frightened at the seine." 

 The value as a food fish is not great, for the flesh behind the gills is black and rank, 

 although in the posterior part of the body it is white, and " the meat near the back- 

 bone is said to be of disagreeable sour flavor." It is therefore much inferior to the 

 mackerel or bonitos. There is, indeed, in the words of Mr. Goode, little probability 

 that " its advent will be of any special importance from an economical point of view, 

 for its oil does not seem to be very abundant, and it will hardly pay, at present, to 

 capture it solely for the purpose of using its flesh in the manufacture of fertilizers." 



The bonito of the American markets, or the belted bonito of others, Sarda medi- 

 terranean has a very robust fusiform body, a long spinous dorsal with about twenty- 

 one spines, eight pinnules above and seven below, largish compressed teeth in the jaws 

 and palatines, toothless vomer, and a good corselet. The color is a dark steel-blue above, 

 silvery below, and, what is characteristic, there are dark stripes running obliquely 

 downwards and forwards. It is a common pelagic fish, and approaches the coasts of 

 both sides of the Atlantic in summer. As a food fish it is of little value. 



We may now consider one of the most important of economical fishes as well 

 as the largest of all fishes, the tunny, Orcymis thynnus. The contour is fusiform 

 and full ; its spinous dorsal fin is long and armed with twelve to fifteen spines, which 

 gradually decrease in length backwards ; the second dorsal and anal are rather short 

 and high, and behind each are eight to ten finlets ; a very distinct corselet is developed, 

 and the body behind has smaller scales ; and palatines as well as vomer have small 

 crowded teeth. In addition to these general characters, the pectorals are rather short 

 and do not extend beyond the end of the spinous dorsal, and the color is dark blue 

 above and grayish below, with silvery spots. While tunny is the commercial name, 

 and that by which it is generally known in the books, it is called by various other 

 names, and is the horse mackerel of the Massachusetts coast. 



As has been just mentioned, it is the largest of the bony fishes. It has been asserted 

 by an Italian naturalist, Cetti, that it occasionally attains a weight of fifteen hundred 

 pounds, and in America, according to Prof. Goode, its weight is not unfrequently 

 twelve to fifteen hundred pounds. Such a size as the maximum, however, is extremely 

 unusual. la the Mediterranean, where systematic fisheries are established, a fish of five 



