6'2 NORTHERN ZOOLOGY. 



spines are robust, the scales strong as in the perches and spari, and the whole head 

 is scaly. Many of them have their pharyngeal teeth " en forme de pave" like the 

 labri ; but they differ from the labri in wanting the double lips, and in having 

 ceecal appendages to the pylorus. Their air-bladder is very large, and is fur- 

 nished, in many of the species, with appendages of very curious forms. The 

 presence or absence of canine teeth, the form of the snout, and the existence or want 

 of barbels on the lower jaw, serve to characterise the minor divisions of the first 

 series. The second series is composed of genera which have a single continuous 

 or very slightly-notched dorsal. They differ more from each other than those of 

 the first series, and it is among them chiefly that combinations of characters 

 analogous to those of the Percoidese occur. Three genera, having seven gill-rays, 

 constitute one subdivision, and are distinguished from each other by the number of 

 pores on the lower jaw, or the presence or absence of scales on the vertical fins. 

 Another subdivision, comprising the Scisenoidese with fewer than seven rays in the 

 gill-membrane, is broken into smaller groups, which are characterised by the form 

 of the lateral line, according as it is continuous or interrupted, or by the presence 

 or absence of simple rays in the pectorals, and by the preoperculum being smooth 

 or toothed. 



The Cottoidese, notwithstanding the peculiarity of their mailed cheeks, form the 

 connecting link between the Percoidese and Scisenoidese. Thus the cottoid 

 Sebastes are so like the percoid Serrani in form, as to be often mistaken for them, 

 and the Scorpsense and Sebastes have palatine teeth like the Percoidese ; while 

 other Cottoideae, the Synanceise for example, have the smooth palates of the Sciae- 

 noideae. 



When we speak of the families in reference to the distribution of the majority 

 of their forms and species, the Percoidese may be considered as belonging prin- 

 cipally to the South Sea and Indian Ocean, the Cottoideae, as affecting the higher 

 northern latitudes, and the Scisenoideee as being more peculiarly an American 

 family, for more than one-third of the genera are proper to the Atlantic shores of 

 that continent, and there are only eight of the thirty * which compose the family 

 that have not one or more species there. The genera peculiar to America are, 

 Ancylodon, Nebris, Lepipterus, Boridia, Conodon, and Eques, inhabiting the 

 intertropical districts, and Leiostomus, Pogonias, Micropogon, and Hcemulon, 

 common to them and the seas of the United States : all these have two dorsals and 



* Cuvier includes thirty-one genera in the family, but the origin of Lonchurm. which consists of one, or perhaps two, 

 species, is unknown. Eleginus, a genus of the Indian and South seas, and one of the eight which have no representative 

 on the Atlantic side of America, has a species on the coast of Chili. 



