544 TELEOSTEI CHAP. 
I. Fins fringed with fulcra, or scales coated with ganoin ; notochord 
usually continuous through the vertebrae. 
Vertebral centra not more than rings; fins with fulcra; scales rhombic, 
united by peg-and-socket joints ; . . 1. Pholidophoridae. F 
Vertebral centra not more than rings; fins with fulera ; scales cycloid 
2. Archaeomaenidae. t 
Vertebral centra complete or with minute perforation; fins with fulera ; 
scales cycloid . : : : . 3. Oligopleuridae. F 
Vertebral centra nearly complete, but with perforation ; no fulera; scales 
eycloid : : ; : . 4. Leptolepididae. + 
Il. Fins without fulera ; Jats w haat ganoin ; vertebral centra com- 
plete. 
A. Supraoccipital separated from the frontals by the parietals or upper 
surface of skull; no adipose fin. 
1. Ventral fins with 10 to 16 rays. 
An intergular bone; parasphenoid narrow . . 5. Elopidae. 
No intergular bone; parasphenoid very broad . 6, Albulidae. 
2. Ventrals with not more than 7 rays. 
Supratemporal very large, plate-like. 
Praemaxillary single, its posterior extremity free from the maxillary ; sym- 
plectic absent ; basis cranii simple . : . 7. Mormyridae. 
Praemaxillary paired, its posterior extremity firmly attached to the maxil- 
d b) d 
lary ; symplectic present ; basis cranii double . 8. Hyodontidae. 
b. Supratemporal small ; maxillary firmly attached to posterior 
extremity of praemaxillary. 
Praemaxillary paired ; a large hole on each side of the skull, between the 
post-frontal and the squamosal ; basis cranii double ; suboperculum absent ; 
ribs sessile. : 5 : : ‘9. Notopteridae. 
Praemaxillary paired ; basis cranil simple ; ; suboperculum reduced ; ribs 
inserted on parapophyses : : . LO, Osteoglossidae. 
Praemaxillary single ; basis cranii simple; suboperculum and interoperculum 
absent ; ribs inserted on parapophyses . . Ll. Pantodontidae. 
c. Supratemporal small; maxillary movable ; ribs sessile ; 
ventral fins below the pectorals 12. Ctenothrissidae. + 
B. Supraoccipital separating parietals, or adipose fin present. 
1. Interoperculum enormous ; symplectic absent ; basis cranii simple 
13. Phractolaemidae. 
2. Interoperculum normal ;-symplectic present ; basis cranii double. 
a. Teeth in sockets ; maxillary firmly attached to praemaxillary. 
Symplectic exposed. ; ; ; . 14. Saurodontidae. T 
b. Teeth not in sockets. 
Symplectic concealed between the quadrate and the hyomandibular 
15. Chirocentridae. 
Postclavicle on outer side of clavicle ; no adipose fin 
16. Clupeidae. 
Postelavicle on inner side of clavicle ; an adipose dorsal fin 
17. Salmonidae. 
Postclavicle absent ; no adipose fin. : . 18, Alepocephalidae. 
+ This sign indicates that the group is represented by fossil forms only. 
