348 
ACTI^^OPTERYGIT. 
Synopsis of Families. 
I. Pelvic fins without anterior spine. 
Vertebrae numerous (above 40), none 
with transverse processes; spinous 
portion of dorsal fin imperfectly 
clitferentiated . 
Vertebrae numerous (above 40), none 
with transverse processes; dorsal 
fin extended, without spinous 
portion . 
Vertebrae numerous (above 40), the ab¬ 
dominal centra with transverse 
processes; dorsal fin remote, with¬ 
out spinous portion. 
II. Pelvic fins with anterior spine. 
Vertebrae numerous (above 30) ; denti¬ 
tion usually feeble ; pelvic fins far 
bach. 
Vertebrae few (about 24) ; dentition 
feeble or absent; pelvic fin-supports 
in contact with postclavicle . 
Vertebrae few (about 24); dentition 
powerful; pelvic fins far back .... 
Crossognathid^ 
[(p. 348). 
AMMODYTIDiE (p. 354). 
SCOMBRESOCID.E 
[(p. 356). 
Atherinid^ (p. 358). 
Mugilid^ (p. 363). 
SPHYR^NIDiE (p. 365). 
Family CROSSOGNATHID^. 
Trunk more or less elongate and laterally compressed. Pre¬ 
maxilla excluding maxilla from border of upper jaw ; cleft of mouth, 
small, with feeble dentition ; opercular apparatus complete, with 
few branchiostegal rays. Vertebrae numerous, probably between 
40 and 50 in total length. Pelvic fins more or less remote, wdthout 
spine, but with only 6 to 8 divided rays; an extended dorsal fin, 
apparently with anterior spinous portion incompletely differen¬ 
tiated ; anal fin small and remote or absent. Scales in regular 
series ; lateral line distinct. 
An imperfectly known extinct family represented only by 
Crossog7iatlius, Syllcemus, and probably allied genera of the Cretaceous 
period. 
Genus CROSSOGNATHUS, Pictet. 
[Foss. Terrain Neocom. Voirons (Paleont. Suisse), 1858, 
pt. iii. p. 27.] 
Head and trunk laterally compressed, and snout acutely pointed 
though not produced. Orbit very large and sclerotic capsule 
