106 
with auditory organ. Gillrakers moderate, short or wanting. 
Luminous organs (photophores) on head and body. 
Synopsis of thie subfam~alies. 
A. Luminous. organs separate, not united in groups. Body 
very low and elongate. No pseudobranchiae. Gill- 
rakers@snOrt-Or ‘wanting eboney. ce Os ie ie Balhae Mele hed eetete Stomiatinae p. 106. 
Z, Luminous organs in groups. Body generally short and 
elevated. Pseudobranchiae present or absent. Gillrakers 
well ideveloped ((alwaysm)iie-seelen- 0-0 stele el ements te Sternoptychinae p. 128. 
1. Subfam. Stomiatinae. 
Body very low, elongate and compressed. A mandibulary 
barbel present or absent. Eye generally large. Gape of mouth 
very wide, oblique. Dorsal generally short or by exception long, 
its origin before or behind ventrals. Adipose fin, if present, 
above or behind anal. Pectorals may be absent, if present, 
very low down. A praeanal adipose fin may be present. 
Ventrals well developed or even long. Caudal forked, its lobes 
often unequal. Scales, if present, very thin, deciduous, cycloid 
and sometimes rhombic. Minute teeth in jaws, those of the 
intermaxilla and mandible may be all or in part enlarged and 
even fang-like; on palate present or absent. Luminous organs 
always separate. There may be opercular luminous organs and 
others before, below and behind eye, the lastnamed even revol- 
ving. Some between the branchiostegal rays. On the body a 
complete ventral series between isthmus and caudal and a more 
lateral one reaching not so far. Scattered between them and 
on the body there may be smaller luminous organs as well 
as whitish punctiform organs on the fins. Branchiostegal rays 
8—2o0. Gillmembranes free from isthmus. Gillrakers well deve- 
loped, short or wanting. Gills 4. No pseudobranchiae. 
Artifical key ito thie cenera, 
I. No pectorals. Origin of long dorsal far in advance of 
anal, its end above anal. No adipose fn......... Idiacanthus p. 107. 
II. Pectorals present. 
A. Dorsal between pectorals and ventrals. Barbel rudi- 
mentary. | Adipose stim spreSeNLt ee ae man. ich etre metl t-te Chauliodus p. 109. 
