153 



x. SAO in an oblique line. AO 57 -f- 23. 

 Second VO slightly dorsally displaced out- 

 side the series. A 15 16. Last Prc near 

 ventral profile. . . , . , M. laternatum p. 156. 



|3. SAO in a blunt angle. AO 56 -f 45. 

 Second VO dorsally displaced outside the 

 series. A. 17 19. Last Prc in lateral line 



or quite near it M. pterotum 157. 



2. Upper jaw extending far behind posterior margin 

 of eye, its posterior end scarcely dilated. I Pol. 



a. Snout prominent M, coccoi p. 158. 



b. Snout not prominent. 

 a. Scales cycloid. 



aa. SAO in an oblique line. Eye 2^3 3. 

 a 2 . AO 7 9 -J- 7 n. 3 or 4 anterior 



AOp above anal M. punctatum 160. 



b*. AO 710 -|- 3 6 ; all AOp behind 



anal M. ajfine p. 161. 



bb. SAO in an nearly right angle. All 



AOp behind anal. Eye 3% 4 M. evermanni p. 162. 



/3. Scales ctenoid. 



aa. SAO in an oblique line. P. 14. AO 



6 8 -f- 5 7 M. spinosum p. 164. 



bb. SAO in an blunt angle. P. 20. AO 



6 8 -f 3 5 M. pristilepis p. 165. 



II. Luminous organs divided by a black septum. 



A. The first PO and the two PVO form a straight, 

 ascending line to the base of the pectorals. The 

 3 anterior VO forming a straight, obliquely ascen- 

 ding line. No luminous patches. {Diaphus). 



1. Antorbital small, (and a small suborbital below 



anterior half of eye, Gilbert) M. dumerili p. 166. 



2. Antorbital large. 



a. A suborbital organ below posterior half of eye M. suborbitale p. 167. 



b. No suborbital organ. 



x. Pol, uppermost SAO and Prc below lateral 



line. End of anal below adipose fin . ... M. caeruleiim p. 168. 

 (3. Pol, uppermost SAO touching lateral line. 

 aa. Uppermost Prc touching lateral line; 

 origin of dorsal above that of ventrals; 

 end of anal below adipose fin M. splendidum 1 70. 



