72 PAPERS FROM TORTUGAS LABORATORY vol. xxxiv 



trolling in the deep water southeast of Loggerhead Key." This species, like the 

 others of the genus, is abundant at Key West only during the winter. A similar 

 seasonal abundance probably prevails at Tortugas. 



This fish reaches a weight as great as 75 pounds. Aside from the larger size 

 attained, it differs from the other local species of the genus in the more posterior 

 position of the anal, which has its origin well behind that of the dorsal, whereas 

 in the other two species its origin is directly under that of the dorsal. Further- 

 more, in this fish the lateral line is abruptly decurved under the second dorsal, 

 instead of being gently decurved as in the other species. 



Cape Cod to Brazil; also Africa. S. F. H. 



Euthynnus alletteratus (Rafinesque). Little tunny 



Common and taken from time to time by trolling. Measurements of one speci- 

 men were as follows: Total length 740 mm.; to base of caudal 655 mm.; depth 

 170 mm.; head 165 mm.; eye 28 mm.; pectoral 112 mm., extending nearly to 

 vertical of nth dorsal spine; dorsal origin above middle of pectoral base and 

 over ventral origin; D. XVI, 12 (or XV-I,i2)-IX; A. 15-VII; teeth on palatines 

 10 or 12, in single series, relatively weaker in adult than in young; gill rakers 28. 



The young to the length of about 150 mm. are caught rather commonly by 

 noddy and sooty terns, and collections of waste from their rookeries usually 

 include fragments, readily recognizable by the peculiar structure of the back- 

 bone. This is composed of 39 vertebrae, and in the subvertebral trellis, which sup- 

 ports the hemapophyses, are 14 closed loculi under vertebrae 17 to 31 inclusive. 



The stomach of a single specimen contained 4 halfbeaks, Hemiramphus, each 

 about 125 mm. long; 1 needlefish, Strongylura raphidoma, about 150 mm. long; 

 and the bones of another. 



The spinous dorsal, though high and strong anteriorly, is depressible in a 

 groove; the pectoral fins, strong and rigid when outstretched, at rest are received 

 in triangular depressions; the ventral fins at rest, too, fit in shallow depressions; 

 and about the jaws and opercular elements no free border projects by a hair's 

 breadth to mar the smoothness of contour and to hinder swift swimming. 



The body is countershaded from dark blue above through lustrous silver to 

 flat white upon the belly. On the posterior half of the body above the lateral line 

 is a ripple pattern in darker shades. The pectoral on its posterior surface is deep 

 blue like the back, on its anterior surface full silver; the ventrals are also blue on 

 their horizontal upper face but flat white below; and on side below pectoral 

 in re-entrant angle of corselet are several round dark spots half size of pupil. 



Warm seas, northward to the middle Atlantic states. W. H. L. 



Family GEMPYLIDAE. Snake Mackerels 



Gempylus serpens Cuvier and Valenciennes 



I have had this fish at Tortugas only in the collection of scraps from the Bird 

 Key tern colony, whence pieces of 4 were obtained in poor condition. To deter- 



