564 
ACTIXOPTERYGII. 
There do not appear to be any fossil remains of species referable 
to this existing genus in the Collection, but the following have been 
described : — 
Acanthurus dtwali, P. Gervais, Zool. et Pal. Prang. (1852), Poiss. 
Poss. p. 8, pi. lxxii. figs. 1, 2. — Middle Eoceno (Calcaire 
Grossier) ; Paris. [Genetically indeterminable imperfect 
fish.] 
Acanthurus haueri, L. Agassiz, Neues Jahrb. 1846, p. 471. 
Iguana (?) haueri, H. von Meyer, in Munster, Beitr. 
Petrefact. pt. v. (1842), p. 33, pi. vi. fig. 12— Tertiary ; 
Vienna. [Teeth.] 
Acanthurus uvalis, L. Agassiz, Poiss. Poss. vol. iv. (1838-44), 
pp. 13, 210, pi. xix. fig. 1. — Upper Eoceno ; Monte Bolca. 
[Imperfect fish ; Bristol Museum.] 
Acanthurus tenuis, L. Agassiz, Neues Jahrb. 1835, p. 293, and 
Poiss. Poss. vol. iv. (1838-42), pp. 13. 208, pi. xxxvi. 
fig. 1. Chcetodon lineatus, G. S. Volta, Ittiolit. Veronese 
(1796), p. cxxxvi. pi. xxxi. fig. 2 ( errore ); H. D. de 
Blainville, Nouv. Diet. d’Hist. Nat. vol. xxvii. (1818), 
p. 354. — Ibid. [Imperfect fish ; Paris Museum of Natural 
History.] 
The so-called Acanthurus gaudryi (A. de Zigno, Atti R. Istit. 
Veneto, vol. xxiii. 1887, p. 14, fig. 2), and Acanthurus gazolce 
(A. B. Massalongo, Specimon I’hotogr. Anim. Poss. Agr. Veron. 
1859, p. 26, pi. vii. fig. 1) from Monte Bolca, do not belong to this 
genus and are probably Chaetodontidao. 
Genus NASEUS (Commerson), Cuvier. 
[Regne Animal, ed. 2, vol. ii. 1829, p. 224.] 
Teeth denticulated. Spinous portion of dorsal fin less extended 
than articulated portion ; anal fin with 2 spines. Scales shagreen- 
like ; one to three (usually two) non-erectile spines on each side of 
the caudal pedicle. 
The skeleton of the existing Naseus hrevirostris is described by 
A. Gunther, Catal. Pishes B. M. vol. iii. (1861), p. 349. 
Naseus rectifrons, Agassiz. 
1796. Chcetodon triosteffus, G. S. Volta, Ittiolit. Veronese, p. cxliii- 
pi. xxxiii. (errore). 
1818. Chcetodon trioslegus, H. D. de Blainville, Nouv. Diet. d’Hist. 
Nat. vol. xxvii. p. 354. 
