XXIII ACANTHOPTERYGII 659 
the anal; latter with 1 or 2 spines only. Ventrals with 1 spine 
and 5 soft rays. 
Embrace about 90 species from the freshwaters of the 
Northern Hemisphere, referable to 12 genera: Perea, Lucioperca, 
Percina, Etheostoma, Boleosoma, Ulocentra, Diplesium, Ammo- 
erypta, Crystallaria, Aspro, Percarina, Acerina. The British 
representatives of this family are the Perch (Perca fluviatilis) 
and the Pope (Acerina cernua). The largest forms are the Pike- 
Perches or Sander (Lucioperca) of Kastern Europe, Western Asia, 
and North America, which reach a length of 4 feet and are 
highly valued for the table. The American Darters (theostoma 
and allies), on the other hand, are among the smallest fishes, but 
many are remarkable for their brilliant coloration. 
Fam. 10. Acropomatidae.—An ill-defined group of marine 
fishes, some deep-sea, placed here provisionally as annectant be- 
tween the Percidae and the Serranidae (Pomatominae), differing 
from the latter in the absence of a subocular shelf Spinous 
dorsal short. 
About 28 species, mostly from the Pacific Ocean, distributed 
in 9 genera: Propoma, Xenichthys, Nenocys, Synagrops, Malac- 
ichthys, Acropoma, Melanostoma, Lpigonus (Telescops), Dinolestes. 
Fam. 11. Serranidae.—Second suborbital with an internal 
lamina supporting the globe of the eye; entopterygoid present ; 
palate usually toothed. Anterior vertebrae without transverse 
processes; all or most of the ribs inserted on the transverse 
processes where these are developed. Two nostrils on each 
side. Gill-membranes free from isthmus; 6 or 7 branchiostegal 
rays; gills 4, a slit behind the fourth; pseudobranchiae usually 
present. Lower pharyngeal bones usually separate. Soft portion 
of dorsal usually not much more developed than the anal. 
Ventral fins with 1 spine and 5 (rarely 4) soft rays. 
One of the largest families of fishes. The principal genera 
may be grouped as follows :— 
SERRANINAE.—Percichthys, Percilia, Lateolabrax, Niphon, 
Morone, Percalates, Ctenolates, Macquaria, Siniperca, Coreoperca, 
Acanthistius, Trachypoma, Centrogenys, Polyprion,  Oligorus, 
Stereolepis, Dinoperca, Liopropoma, Aulacocephalus, Plectropoma, 
Lpinephelus, Cromileptes, Paranthias, Serranus, Centropristes, 
Chelidoperca, Gilbertia, Caesioperca, Caprodon, Anthias, Callan- 
thias, Pseudoplesiops, Plesiops, Trachinops. 
