121 



an incomplete lateral series of luminous organs, besides 2 

 opercular ones, a series between the branchiostegal rays and 

 a suborbital one. Head compressed, conical. Gape of mouth 

 very wide, bordered superiorly by the small intermaxillary 

 and the very long, slender, sickle-shaped maxillary. Infraorbital 

 bone dilated, covering at least a considerable part of the 

 cheek. Lower jaw projecting, with a prominent inferior pos- 

 terior angle, enclosed between the maxillaries. Dorsal shorter 

 than anal, the origin of both opposite or nearly so, both 

 situated behind the middle. Pectorals in the lower half of 

 the height. Ventrals before middle of length. Caudal forked. 

 Adipose fin nearly always present. Long, fanglike teeth, rather 

 regularly distributed in the upper and lower jaw, with much 

 smaller ones in the spaces between them. Vomer with or 

 without teeth. A series of teeth on palatines and pterygoids. 

 Gillopening very wide. Gillmembranes free from isthmus. 

 Pseudobranchiae none. Gillrakers very long and slender. Bran- 

 chiostegal rays short, 11-14. 

 Bathypelagic fishes. 



Synopsis of the species. 



1. Extremely thin, partly concealed, large scales, 2 hooked 

 vomerine teeth. Origin of dorsal above the 2 lld or 3 rd 



anal ray G. rhodadcnia p. 1 2.1. 



2. No scales. Vomer edentulous. Origin of dorsal and anal 



in the same vertical G. elongatum p. 122. 



i. Gonostoma rhodadenia (Gilbert). 



Cyclothone rhodadenia Gilbert, Bull. U. S. Fish. Comm. XXIII. 2. (1903) 1905, p. 602. 

 Gonostoma rhodadenia Max Weber, Siboga-Exp. Fische, 1913, p. 18. 



B. ii; D. 14; A. 3031; P. 1113; V. 8. 



Height about 7, head about 4 ! / 2 , eye 6 7 3 / 5 , 2 / 3 of length of 

 snout and of the interorbital space, which contains a pair of 

 narrow ridges, lengthwise parallel, which fork anteriorly, the 

 branches diverging to either side of nostrils, posteriorly, these 

 ridges extend along the sides of the occiput where they gently 

 diverge. Suborbital bone covering much less than half cheek, 

 forming a sheet overlaying upper portion of maxillary for its 

 entire length. Pointed symphysis of mandible very prominent. 

 Gape of mouth very wide. Maxillary curved, reaching to angle 



