556 
ACTINOPTERTGir. 
by the extinct genus Odonteus with the following species, of which 
there are no remains in the Collection:— 
OdonteuspygmcBUs, A. de Zigno, Mem. E. Istit. Veneto, vol. xviii. 
(1874), p. 291, pi. X. fig. 1 ; r. Bassani, Palaeont. Italica, 
vol. iii. (1898), p. 83, pi. ix. fig. 5. —Upper Eocene; Monte 
Bolca, near Verona. [Imperfect fish ; Zigno Coll., Uni¬ 
versity of Padua.] 
Odonteus sparoides, L. Agassiz, Poiss. Eoss. vol. iv. (1839), p. 178, 
pi. xxxix. fig. 2; E. Bassani, Atti Soc. Veneto-Trent. 
8ci. jVat. vol. iii. (1876), p. 176. Odonteus sparoides, var. 
depressus, E. Bassani, Palseont. Italica, vol. iii. (1898), 
p. 83, pi. viii. fig. 2.—Ibid. [The type species. Imper¬ 
fect fish; Paris Museum of Natural History.] 
Odonteus aff. sparoides, E. Bassani, Atti E. Accad. Sci. ISTapoli 
[2] vol. iii. (1889), no. 6, p. 94, pi. xiii. fig. 3.—Lower 
Miocene; Chiavon, Vicentin. [Imperfect fish ; Piovene 
Coll., Lonedo.l 
Division D. CH-ETODONTIFOEMES. 
As Perciformes, but brain-case very short, and facial region of 
shull much produced, with terminal small mouth. Specialisation 
resulting in degeneration of fins and shortening of vertebral axis. 
Synopsis of Families represented hy Extinct Genera or Species. 
I. Eins normal, the dorsal spines well-developed. 
Maxilla separate from premaxilla .... Ch^todontio^ (p. 556). 
Maxilla fused with premaxiUa . Acronurid^e (p. 562). 
II. Fins reduced, the dorsal spines rarely more than 3, usually absent 
{Plectognathi). 
Maxilla fused with premaxilla, but 
marginal teeth distinct . BALisxiDiE (p. 565). 
Maxilla fused with premaxilla, and no 
distinct marginal teeth .. Gymnodontid^ (p. 570). 
Family CH^TODONTID^. 
Trunk deepened, with scales more or less densely covering arti¬ 
culated portions of median fins. Maxilla separate from premaxilla ; 
teeth minute and clustered. Vertebrae 9 or 10 in abdominal, 13 or 
14 in caudal region. Anal fin with 3 or 4 spines. Scales small or 
minute, more or less ctenoid. 
Carnivorous fishes chiefly occurring in tropical seas in the neigh- 
