26 
SCANDINAVIAN FISHES. 
have departed from the later opinion of Gunther and 
others who have followed him, according to which 
these fishes should be divided into two families. Some 
exception, too, may be taken to this arrangement, on 
the ground that the characters given therein draw a 
wide distinction between forms that are obviously most 
closely related in other respects, e. g. Boccus and Perea. 
The character given by Gunther, as well as by Jordan 
and Gilbert", as a distinction between these families, 
that the Percidce have fewer pyloric appendages than 
the Serranidce, does not hold good in the case of Boccus , 
as B. labrax has only 5 pyloric appendages 5 . The scheme 
given above shows, however, that in the Scandinavian 
Fauna we may follow the division proposed, whether 
we decide to employ only external characters, or in- 
ternal ones which are not so easy to fix. 
Genus PERCA. 
The shape of the body an oblong oval , laterally compressed to some extent. The scales of average size , with sharply 
denticulated margin. A spine behind the gill-cover. The preoperculum , shoulder girdle and preorbital bones serra- 
ted. The cheeks scaly , but the upper part of the head naked. Small teeth , of equal size, set in car diform bands , 
on the intermaxillary bones , the lower jaw, the vomer and the palatine bones. The tongue without teeth. Only 3 
pyloric appendages. Pseud obranchice complete , though sometimes overgrown. Branchial membranes separate, each 
with 7 rays. In the anterior dorsal fin from 13 to 15 rays. In the anal fi.n 2 spinous rays; the base being 
shorter than that of the posterior dorsal fin. In the caudal fin at least 15 branched rays. 
As our knowledge of Perea Schrenckii of Turkestan 
is only partial, and as Jordan and Gilbert 4, have re- 
ferred Perea gracilis of Canada to the common Ame- 
rican perch, we can scarcely claim to know more than 
one species of the genus Perea , our common perch. This 
species, however, contains several varieties, which are 
spread over the east of North America, the whole of 
Europe and the west of Siberia, thus forming one of 
the remains of the prehistoric connection across the 
Atlantic between the Old World and the New A 
THE PERCH. 
PERCA FLUVIATILIS. 
Plate 3, fig. 1. 
R. hr. 7; D. 15 e 
13 / 
15 + #*; L. lat. 50—70. 
A. 
; P. 1 + 11 + 3 A ; V. V 5 ; C. # + 
Syn. Perea fluviatilis et major auctorum, Art., Gen. Pise., p. 39; 
Synon., p. 66; Descr. Spec., p. 74. 
Perea fluviatilis , Lin., Syst. Nat., ed. X, p. 289; Bluch, 
Fische Deutschl., tab. LII; Retz., Fn. Suec. Lin., p. 335; 
Cov., Val., Hist. Nat. Poiss., II, p. 20; Pall, Zooyr. R. 
Ms., III, p. 248; Nilss., Prodr. lehth. Scand., p. 81; 
Ekstr., Wright, Bkand. Fiskar, ed. 1, p. 1, tab. I, fig. 
1; Bonap , Icon. Fn. Ital., Ill, n:o 87, p. 79, tab. fig. 1; 
Krgyer, Damn. Fiske, I, p. 1 ; Nilss., Skand. Fn., Fisk., 
p. 5; Gunth., Brit. Mus. Cat., Fish., I, p. 58; Sieb., 
Siisswasserf. Mitteleur., p. 44; Coll., Norges Fiske, Chr. 
Vid. Selsk. Forh. 1874, Tillsegsh., p. 15; ibid. 1879, n:r 
1, p. 5; Malm. Ghgs, Boh. Fn., p. 374; Winther, Zool. 
Dan., Fiske, p. 2, tab. I, fig. 1 ; Feddersen, Naturli. Tidskr. 
Kbhvn, 3 R., XII, p. 71; Day, Fish. G:t Brit., Irel., I, 
p. 2; Lilljeborg, Sv., Norg. Fiskar, I, p. 46; Reuter et 
Sundman, Finl. Fisk., tab. IX. 
Perea vulgaris, Gronovius et Schjeffer; P. helvetica, Gron.; 
vide Gunther, 1. c. et Siebold, 1. c. 
a Syn. Fish. N. Amer., 1. c., pp. 486 and 527. 
6 Cf. Day, Fish. G:t Brit., Irel., pt. I, p. 9. 
c Syn. Fish. N. Amer., 1. c., p. 524. 
d Smitt: Ur vdr tids forskning no. 29, pp. 58, etc. 
e Sometimes 14, in the American variety sometimes 13. 
f » 14. 
s » 9. 
h » 2 + 10 + 2 or 2 + 9 + 3. The middle figures indicate the number of the branched rays. 
1 » #+16+#. The middle figure indicates the number of the branched rays. 
