lOO Memoir Sears Foundation for Marine Research 



9b. Gill membranes broadly united; branchiostegal 

 rays 2. Bathylagidae, Part 4.** 



8b. Lateral-line scales extending out onto caudal fin; adi- 

 pose dorsal fin over or posterior to rear end of base of 

 anal fin. Argentinidae in part (Nansenia, 



Microstomatinae in part), Part 4.*' 

 6 b. Rear end of upper jaw reaching beyond front of eye. 

 10 a. Some of jaw teeth large, fang-like, conspicuous. 



I I a. Eye about 33°/o or more of hi; origin of anal pos- 



terior to origin of dorsal by a distance less than 

 5o''/o of hi. Omosudidae, Part 5. 



I I b. Eye only about i5''/o of hi; origin of anal posterior 



to origin of dorsal by a distance nearly equal to hi. 

 Evermannellidae in part, Part 5.''* 

 lob. None of jaw teeth much enlarged or fang-like. 



12 a. Upper jaw extending rearward past eye for a dis- 

 tance at least twice the length of eye.*^ 

 13 a. Rear end of base of dorsal anterior to origin of 

 anal by a distance at least 50 "/o of hi. 



Synodontidae, Part 5. 



1 3 b. Rear end of base of dorsal only slightly ante- 



rior to origin of anal. 



Bathysauridae in part. Part 5.'" 

 12 b. Upper jaw extending rearward past eye for a dis- 

 tance no longer than length of eye, and relatively 

 shorter than this in most. 



14 a. Dorsal profile of head deeply concave close in 



front of eye; insertion of pelvics anterior to 



origin of rayed dorsal by a distance nearly or 



quite as long as eye. Scopelosauridae, Part 5. 



14 b. Dorsal profile of head close in front of eyes only 



weakly concave at most; insertion of pelvics 



under or posterior to origin of rayed dorsal. 



15 a. Upper jaw extending rearward beyond 



eye for a distance about as long as eye; 



dorsal profile of head weakly concave; 



body deepest about at gill opening. 



Neoscopelidae in part 

 {Scopelengyi)^ Part 5.** 



46. See also Key A, 13 b; Key B, Sbj Key D, 4 b. 47. See also Key D, i b. 



48. For species having eyes with pupil above center and capable of being directed upward, see Key D, 5 b. 



49. In small specimens of some species of Trachinocephalus the upper jaw does not extend rearward as far as this. 



50. For those without adipose fin, see Key A, 7 b. 51. For those with photophores, see Key C, 14 b. 



