PERCHES. 
25 
PERCOMORPHI. 
The families of the Percomorph series, with scales usually ctenoid and uniformly covering the whole body, are further 
distinguished by the lateral compression of the body, which is more or less deep even at the peduncle of the tail , 
and also by the general strength of the spinous rays in the dorsal , anal and ventral fins. The suborbital ring 
has no osseoits connection with the preoperculum. 
Although we have just stated that one of the cha- 
racters which distinguish most of the forms within this 
series, namely the clenticulation of the preoperculum, 
may appear in the mackerel-series as a character of the 
younger specimens, thus showing that the latter series 
has, in this respect at least, reached a higher degree of 
metamorphosis, still, according to established custom and 
the precedent set by Cuvier, we place the Percomorph 
series first. It is this type that gives the clearest idea 
of the perfection of the Eleutherognates, for in it no 
special organic system has been stunted or developed 
at the expense of the others and thus in any respect 
caused a distortion of the regularity of the Teleo- 
steous form. 
The families of the Scandinavian Fauna which 
belong to this series may be distinguished by means 
of the following scheme. 
1: Ventral lins regular, with 1 spinous and 5 soft rays. 
A: Branchiostegal rays at least 5. Chin without 
or with only rudimentary barbels. 
a: Preorbital bone covering only the anterior 
and superior parts of the maxillary bone 
when the mouth is closed. 
a: Vomer with teeth Percidce. 
fj: Vomer toothless Scicenidce. 
b: Preorbital bone covering the whole of the 
maxillary bone, when the mouth is closed Sparidce. 
B: Branchiostegal rays 4. Chin with large and 
mobile barbels __ Mullidce. 
II: Ventral fins with 1 spinous ray and more (or less) 
than 5 soft rays . Berycidce. 
Fam. V K l\ ( I I) 2E. 
Exterior bones of the head, at least the preoperculum, jagged or denticulated. Scales denticulated. Spinous- rayed 
part of the dorsal fin or the anterior dorsal film without scales, and longer than the soft-rayed part or posterior 
dorsal fin. Simple, conical teeth on the lower jaw, the intermaxillary bones , the vomer and the palatine bones. 
The ventral fins thoracic, with one spinous and five soft rays. Chin without barbels. 
In number of species the Percoid family is one of 
the largest among the Teleostei. Gunther gives in his 
Catalogue more than 700 species which must be referred 
to this family according to his later opinion*. They 
belong to the salt and fresh waters of the tropical and 
temperate zones: only a few are met with north of 
the polar circle, and among these we find just those 
species which belong to Scandinavia. Their geological 
age is, as far as v r e know, not great, but one species 
of the true genus Perea has been found in the Miocene 
strata at Oeningen. The genera which belong to the 
Scandinavian Fauna may lie distinguished by means of 
the followdng scheme: 
A: Anal fin with 2 spinous .rays. (Number of 
vertebrae 30 — 45: Percince ) 
a Cope, (p. p.) Acanth. Perciformes, Gunther (p. p.) 
b Introd. Stud. Fish. 
a: Two dorsal fins. 
a: The teeth of the jaws and palate 
equal in height (no canine teeth) Perea. 
(3: Between the jaw-teeth and the palatine 
teeth large canine teeth far apart from 
each other Stizostedium . 
b: One dorsal fin Acerina 
B: Anal fin with 3 spinous rays. (Number of 
vertebrae about 24: Serranince ) 
a: Two dorsal fins Roccus. 
b: One dorsal fin Polyprion. 
Each of these genera is represented in our Fauna 
by onl} 7 one species. On that account, and because the 
Scandinavian forms which belong to this family are not 
so numerous as to render it difficult to distinguish 
them without any further division of the family, v T e 
Scandinavian Fishes. 
4 
