ACRONURIDjE. RALISTID.JE. 
565 
1838-42. Naseus reetifrons, L. Agassiz, Poiss. Foss. vol. iv. pp 13, 
213, pi. xxxvi. fig. 3. 
1859. Naseus reetifrons , A. B. Massalongo, Specimen Photogr. Anim. 
Foss. Agr. Veron. p. 22, pi. xii. fig. 1. 
1876. Naseus reetifrons, F. Bassani, Atti Soc. Veneto-Trent. Sci. Nat. 
vol. iii. p. 178. 
Type. Imperfect fish ; Paris Museum of Natural History. 
A species attaining a length of about 0'2o. Maximum depth of 
trunk not much less than length from pectoral arch to base of 
caudal fin. Dorsal fin with 6 spines and 30 to 35 articulated rays ; 
anal fin with about 24 articulated rays besides the two spines. 
Form, tj- Loc. Upper Eocene : Monte Bolea, near Verona. 
41890 . Imperfect fish, 0 - 2 in length. Purchased, 1870. 
21393 . Fragments of largor specimen. Purchased, 1847. 
43490 . Small specimen 0-05 in length, in counterpart, probably 
young of this species. 
Presented by F. G. Beckford, Esq., 1872. 
The following extinct spocies has also been described but is not 
represented in the Collection : — 
Naseus nuchalis, L. Agassiz, Neues Jahrb. 1835, p. 292, and 
Poiss. Foss. vol. iv. (1838-42), pp. 13, 212, pi. xxxvi. 
fig. 2. Chastodon nigricans, G. S. Volta, Ittiolit. Veronese 
(1796), p. c. pi. xxii. fig. 1.— Upper Eocene; Monte 
Bolea. [Imperfect fish ; Paris Museum of Natural 
History.] 
Family BALISTIDiE. 
Trunk deepened. Maxilla fused with premaxilla; few large 
incisiform teeth in single or double series. Vertebra 7 to 9 in 
abdominal, 10 to 14 in caudal region. Fins more or less reduced, 
spines being always absent in the anal fin ; pelvic bones firmly 
united. Skin with minute tubercles or bony plates. 
Small littoral fishes, chiefly of tropical regions. 
Synopsis of Extinct Genera and Genera represented by 
Extinct Species. 
I. With minute dermal tubercles. 
Six or seven laige dorsal spines ; pos- 
terior dorsal and anal small .... Spinacanthus (p. 566). 
