FISHES OF NEW YORK 385 



one half the snout; the fin is followed by eight finlets, which de- 

 crease in size posteriorly. The anal origin is below the inter- 

 space between the end of the second dorsal and its first finlet; the 

 anal base is as long as the second dorsal base; its first ray is as 

 long as the snout, its last ray is one half the short diameter of 

 the eye; it is followed by seven finlets, decreasing in size poster- 

 iorly. The middle caudal rays, from end of keel, are one fourth 

 as long as the outer rays, which are one half as long as the head; 

 the caudal lobes form a very obtuse angle with the caudal 

 peduncle. The ventral origin is directly under the root of the 

 pectoral; the fin is as long as the snout and eye combined, the 

 ventral sheath about as long as the fin. The pectoral is falcate, 

 many-rayed, its length four ninths of length of head; the fin 

 reaches to below the last spine of the first dorsal. D. X-12- 

 VIII; A. 13- VII; V. I, 5; P. 22; B. VII. 



Color dark blue above with reticulated markings on the back, 

 chiefly in the second half of the length and all above the lateral 

 line; sides, lower parts and head silvery; ventral dark. 



The frigate mackerel is found in all warm seas and ranges 



northward occasionally to Cape Cod; it is a rare visitor in our 



waters, but sometimes appears in immense schools. It has little 



value as food. It reaches the length of 16 inches. The species 



was unknown on our shores till 1880, when it arrived in almost 



countless numbers. Its food is the same as that of the common 



mackerel. 



Genus gym^osaroa Gill 



This genus according to Liitken differs from Thunnus l)in 

 the absence of teeth on vomer; 2) by the complete absence of 

 scales outside of the corselet (for in Thunnus of the same 

 size the skin is covered with small scales; and the limits of the 

 corselet in the tunny and albicore are obscure, so that it can not 

 properly be said that they have distinct corselets), and 3) by an 

 important osteologic character, namely the peculiar develop- 

 ment, in the form of a network or trellis, of a portion of the 

 abdominal part of the backbone, between the vertebrae proper 

 and the hemapophyses. Vertebrae 38. Species of smaller size 

 than the tunnies, also pelagic, and of little value as food. 



