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. 

 loa. Some of jaw teeth large, fang-like, conspicuous. 



1 1 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. 



lib. 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. 



1 2 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.^' 

 1 2 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 

 (Scope/engys), Part 5.** 



46. See also Key A, 13 b; Key B, 8 b; Key D, 4b. 47. See also Key D, ib. 



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 Trac/iinocephalus the upper jaw does not extend rearward as far as this. 



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



