POPE. 
41 
THE POPE OR RUFF (sw. gers.) 
ACERINA CERNUA. 
Plate III, fig. 3. 
Eyes set about half-way along the head (length of the snout nearly equal to the distance from the posterior 
orbital margin to the end of the gill-cover). Number of spinous rays in the dorsal fin 16 at most. From 36 
to 40 scales in the lateral line. Colour of the body grayish or greenish, brown with dark spots on the sides and 
the unpaired fins: the belly whitish. 
R. hr. 7; D. -p-; A. P. 2 + 11 + 1°; V. l / 5 ; C. x+15 
+ x d -, L. lat. 3G — 39 e . 
Syn. Cernua , Perea minor, Aurata et Porcellus Auctorum , Art., 
Ichth., Gen., p. 40; Syn., p. 68; Spec., p. 80. 
Perea cernua, Lin., Syst. Nat., ed. X, tom. I, p. 294; Retz. 
Fn. Su. Lin., p. 338; Gthr ( Acerina ), Brit. Mus. Cat., Fish., 
I, p. 72; Coll., Norrj. Fiske, 1874, p. 16; L.jbg, S., Norg. 
FisJcar, I. p. 66. 
Acerina vulgaris, Cuv., Val., Hist. Nat. Poiss., Ill, p. 4; 
Nilss., Prodr. Ichth. Sc., p. 78; Ekstr., Vet.-Akad. Handl. 
1831, p. 96; Id. et W. v. Wright, Skand. Fiskar, ed. 1, 
p. 9, tab. 1. fig. 2; Krgyer, Damn. Fiske, I, p. 43; Nilss. 
Sk. Fn., Fisk., p. 28; Winther, Zool. Dan., Fiske, p. 4; 
Feddersen, Nat. Tidskr. Kjobenh., 1879, p. 72. 
To the casual observer the Pope seems closely to 
resemble the Perch, and in its way of life too there is 
much to remind us of the latter. Its body is almost 
the same in shape as that of the Perch, but is more 
rounded, for though the dorsal edge is sharp, the belly 
is not so much compressed as in the Perch, a circum- 
stance which gives the Pope an appearance of being 
fatter and in better condition. For this reason in some 
parts of Sweden the name of skattbonden (rich peasant) 
is bestowed upon it. Although the body is covered 
with hard scales which are firmly fixed and ctenoid 
(denticulated at the margin), still it does not feel rough, 
as it is enveloped in a thick, clammy mucus. This 
secretion is especially noticeable on the surface of the 
head, and has given rise to several provincial names by 
which the Pope is known, as for instance snorgers ( snor 
= the secretion of the nose), snorpels ( pels — skin), 
snorluf ( luf — forelock, forehead) etc. The back is of 
a grayish brown olive-colour, and the single dorsal fin 
is of the same colour with a touch of yellow and is 
marked with dark dots, which are set in rows on the 
membrane between the rays. On the back too there 
are large, dark spots, and the sides, which are yellowish 
gray or brass-coloured, are marked with dots or small 
spots. The length of the dorsal fin, the relative length 
of which increases with age, is about half the length 
of the body. The spinous rayed part, which also in- 
creases proportionally in the same way, forms about 
2 / 3 of the fin. Both the spinous-rayed and soft-rayed 
parts — - the depression between which recalls to mind 
the two separate dorsal fins in the Perch and Pike- 
perch — have a rounded (convex) margin; and in both 
of them the 4th and 5th rays are the longest. In the 
spinous-rayed portion the last ray is longer than the 
next one before it, a circumstance which indicates that 
the former really corresponds to the first ray in the 
second dorsal fin in the case of those genera of the 
family which have two distinct dorsal fins. The head 
is of the same colour as the back ; it is oval and some- 
what compressed, the depression on the forehead and 
just behind the eyes giving the snout a swollen ap- 
pearance. It is fairly large in proportion to the length 
of the body, being from 27 to 29 % of that length. 
Its exterior bones are pierced by a system of ducts, the 
so-called muciferous ducts, which are larger in the Pope 
than in the Perch or the Pike-perch. These ducts com- 
prise part of the organs of sensation connected with the 
lateral line, a structure peculiar to fishes and the ba- 
trachiansA The orifices of these ducts form, in the case 
of the Pope, the so-called muciferous cavities, which 
are lined with a membrane which freely secretes the 
mucus. There are three of these oval cavities on the 
13 i 14 
“ Sometimes — 1. — 
12 13 
— 1 . — 1 . 
11 10 
16 
To - 
6 Sometimes "/»• In a specimen from the island-belt off Stockholm we find 3 / 6 . 
c Sometimes 2 + 10 + 2 1. 2+12 + 1 1. 1 + 12 + 1 1. 2+11. 
d In a specimen from Archangel the numbers are x + 14 + x. 
e 40 according to Day, 1. c. 
f See Leydig, Lehrb. d. Histologie, p. 201 and Festschr. z. Feier d. 100-jcihr. Best. d. Naturf. Ges. z. Halle, 1879; F. E. Schultze, 
Arch. Mikr. Anat., VI (1870), p. 62; B. Solger, ibid. XVII (1879), p. 95 and 458, XVIII (1880), p. 364, with the passages on this subject 
which are there quoted. 
Scandinavian Fishes. 
6 
