570 
ACTINOPTERTGII. 
name of Ancistrodon vicentinus {loc. cit. 1883, p. 667, pi. xix. 
fig. 10)^— 
P. 5925. Pive teeth of the form named Coraoj Jissuratus hy T. 
C. Winkler, Archiv. Mus. Teyler, vol. iii. (1874), p. 300, 
pi. vii. fig. 4, and ibid. vol. iv. (1876), p. 27, pi. ii. figs. 11, 
12; Middle Eocene, Woluwe St. Lambert, Brussels. 
Noticed as Ancistrodon Jissuratus by A. S. Woodward, 
Geol. Mag. [3] vol. viii. (1891), p. 108, and identified by 
Dames with Sargus ? armatus (P. Gervais, Zool. et Pal. 
Eranc. 1852, Poiss. Eoss. p. 5, pi. Ixix. figs. 9, 10) from 
the Erench Eocene; recorded by Dames (loc. cit. 1883, 
p. 664, pi. xix. fig. 2) as Ancistrodon armatus. 
Presented by Monsieur A. Houzeau de Leliaie^ 1889. 
The name Glyptoceplialus radiatus is proposed by Agassiz (Poiss. 
Eoss. vol. ii. pt. ii. 1844, p. 264) for the tuberculated skull of a 
supposed member of the Balistidse from the London Clay of Sheppey, 
said to have been placed in the British Museum by Konig and 
labelled by him Ephippus oivenii. This is the head of a Siluroid 
fish already described above (p. 330) as Bucklandium diluvii. 
Family GYMNODONTIDJE. 
Trunk deepened. Maxilla fused with premaxilla; no separate 
teeth, but often dental plates imbedded in the bone of the jaw, 
these continually replaced by vertical successors. Vertebrae usually 
much reduced. No spines in dorsal or anal fins. Skin usually 
with small spines or spinous bony plates, sometimes naked. 
Chiefly tropical and sub-tropical marine fishes, most of them 
surface-dwellers and capable of inflating their body by filling the 
distensible oesophagus with air. A few Tetrodonts live in large 
rivers. No clearly recognisable extinct genera are known. 
Synopsis of Genera represented by Extinct Species. 
I. Caudal region normal. 
Each jaw with median suture at sym¬ 
physis, and only marginal dental 
plates ; small dermal spines without 
expanded root . Tetrodon (p. 571). 
Each jaw fused at symphysis ; marginal 
and inner dental plates; dermal 
\ 
^ See also Part III, p. 283. 
