XXIII ACANTHOPTERYGII 669 
23, with sessile ribs and no parapophyses, the epipleurals inserted 
on the ribs. Body covered with very small scales. Vertical 
fins elongate, with strong spines, 6 or 7 in the anal. Ventrals 
with 2 spines and 35 soft rays between them. 
A single recent genus, 7euthis, with about 30 species, herbivor- 
ous fishes from the Indian and Western Pacific Oceans. Accord- 
ing to Bottard' the sting from the spines of these fishes is much 
dreaded. Archaeoteuthis, from the Oligocene of Switzerland. 
Fam. 31. Osphromenidae.—Second suborbital with a more or 
less developed internal lamina; entopterygoid present; palate 
toothed. Most of the praecaudal vertebrae with transverse pro- 
cesses, to which the ribs are attached. Two nostrils on each 
side. Gill-membranes attached to isthmus; 4 to 6 branchio- 
stegal rays; gills 4, a slit behind the fourth; pseudobranchiae 
absent. Lower pharyngeal bones separate. Vertical fins very 
variable in extent, the spines sometimes very numerous, some- 
times absent. Ventral fins with not more than 5 soft rays, 
sometimes reduced to a filamentous ray. A superbranchial re- 
spiratory organ, situated in a cavity above the gills. 
Freshwater fishes having much in common with the Anaban- 
tidae, and likewise confined to South-Eastern Asia and Africa. 
Only 22 species are known, referable to 7 genera: Helostoma, 
Polyacanthus, Osphromenus, Trichogaster, Luciocephalus, Betta, 
and Mieracanthus. The latter, the only African representative 
of the family (one species from the Ogowe), hardly differs from 
the Malay genus Betta. Most of the Osphromenidae are notable 
as aquarium fishes. The largest species, the Gourami (Osphro- 
menus olfax), growing to a length of 2 feet, from the Malay 
Archipelago, is one of the best flavoured fishes of the Far East and 
has been acclimatised in India, the Guianas, and Mauritius. <A 
domesticated variety of the Chinese Polyacanthus opereularis, 
known as Macropodus viridi-auratus, remarkable for the beauty 
of its form and colour, readily breeds in our aquariums. Like 
the Gourami, the male constructs a nest of air-bubbles, strengthened 
by a buccal secretion, and watches over the eggs and young. The 
little Betta pugnaz, from South-Eastern Asia, derives its name from 
its excitable nature, which causes specimens to be kept by the 
Siamese in glass vessels where they engage in fights, special 
breeds being cultivated for the purpose. According to Cantor, 
1 Poissons venimeux (Paris, 1889), p. 169. 
