88 
ACTINOPIEEYGTI. 
[As Sjjathodactylus, but dorsal fin 
longer than deep and opposed 
to pelvic fins . Cladocyclus (p. 107).] 
(b) A presymphjsial bone in man¬ 
dible. 
Similar skull and jaws, but the 
teeth compressed to a sharp 
edge, and a series of nutritive 
notches on the inner face of the 
jaw below the alveolar border . Saurodon (p. 111). 
Teeth compressed to a sharp edge, 
with germs of successors arising 
on the inner face, where there 
is a series of nutritive foramina 
below the alveolar border .... Saurocephalus (p. 113). 
Genus CHIROCENTRUS, Cuvier. 
[Eegne Animal, vol. ii. 1817, p. 178.] 
Trunk elongated and laterally compressed; abdomen trenchant. 
Teeth laterally compressed, firmly fixed in shallow sockets; at least 
one pair of premaxillary teeth enlarged, the other premaxillary and 
maxillary teeth small and in single series; mandibular teeth very 
large, in a single series ; minute villiform teeth on the palatines, 
pterygoids, and tongue. Eight branchiostegal rays. Eibs very 
delicate. A long pointed osseous appendage at the base of each 
pectoral fin; pectoral fins of moderate size, the length of the rays 
much less than that of the head with opercular apparatus; pelvic 
fins very small; dorsal fin short, opposed to the anal, which is much 
extended but not elevated into a pointed lobe in front; caudal fin 
deeply forked. 
This is the sole surviving genus of the famil}', and is represented 
only by one existing species in the Indian Ocean. 
Chirocentrus (?) polyodon, Gunther. 
1876. Chii'ocenti'us {?) polyodon, A. Giinther, Geol. Mag. [2] vol. iii. 
p. 438, pi. XV. fig. 3. 
Type. Dentar}^ bone ; British Museum. 
A species doubtfully of this genus, known only by fragmentary 
jaws. The teeth in the dentar}^ are slender, numerous, mostly 
large but irregular in size, and very closely set; those of the maxilla 
are about as large as the hindermost teeth of the dentary. 
Form. Log. Freshwater Tertiary Lignite : Padang, Sumatra. 
