POPK. 



41 



THE POPE OR RUFF (sw. gkhm.) 



ACERINA CERNUA. 



Plate III, lis- 3. 



Eyes set ahoiit haJf-iraii nlmi;! Ilic head (Icii^ulli (if tlic snout iic;ii-l\- ('(iiial to the rlistance from the posterior 



orbital margin to tlic end of the irill-oover). Number of sphious nii/s in the ilorsal tin Ki at most. From 30 



to 40 scales in the lateral tine. Colour of the Jtodi/ f/rai/ish or greenish liroini irith dark spots on the sides and 



the unpaired fins: the heUji irjiitish. 



It. bi: 



IK 



14" 

 12 ' 



A. --; P. 2+U + l' 

 



V. .r+15 



-\-x''; L. lat. 36—39' 



Syn. Ccrnua, Perca minor, Aurata et Poreellus Auctormn, Art., 

 fdith., Gen., p. 40; Syn., p. 68; Spec, p. 80. 

 Perca cernua, Lm., aS'^**. Nat., ed. X, toin. I, p. 294; Retz. 

 Fn. Sii. Lin., p. 338; Gthr (Acerina), Brit. Mus. Cat., Fisli., 

 I, p. 72; Coll., Norij. Fiske, 1874, p. 10; L.inG, S., Norg. 

 Fiskar, I. p. 66. 

 Acerina vulgaris, Cuv., Val., Hist. Nat. Poiss., Ill, p. 4; 

 NiLss., Prcidr. Iclitli. Sc, p. 78; Ekstk., Vet.-Akad. Haiidl. 

 1831, p. 96; Id. et W. v. Wright, Skand. Fiskar, ed. 1, 

 p. 9, tab. 1. fig. 2; Kroyer, Damn. Fiske, I, p. 43; NiLSS. 

 Sk. Fn., Fisk., p. 28; Winther, ZooL Ban., Fiske, p. 4; 

 Feddersen, Nat. Tidskr. Kjobenli., 1879, p. 72. 



To the casual ob.server the Pope .seems closely to 

 resemljle 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 sha])e as that of the Perch, but is more 

 rounded, for though the dorsal edge is sharp, the belly 

 is not so mucli compressed as in the Perch, a circum- 

 stance \\liicli gives the Pope an appearance of being 

 fatter and in better condition. For this reason in some 

 parts of Sweden the name of skatthonden (rich peasant) 

 is bestowed upon it. Although the body is covered 

 with hard sc-ales which are tirmlv 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 h;is given rise to several provincial names liy 

 which the Pope is known, as for instance snorgers {snor 

 — the secretion of the nose), snorpels {pels — skin), 

 snorhtf {luf — forelock, forehead) etc. The back is of 

 a grayish bi-own olive-colour, and the single dorsal fin 

 is of the same colour with a touch of yellow and is 



13 , 14 , 14 , 15 16 



" Sometimes -—1. — 1. — 1. — I. — . 



12 13 11 10 10 



* Sometimes - ,. In a specimen from the island-belt oflE Stockholm we find ^ g. 



' Sometimes 2+10 + 2 1. 2+12 + 1 1. 1 + 12 + 1 1. 2+11. 



'' In a specimen from Archangel the numbers are x + H + .('. 



' 40 according to Day, 1. c. 



/ See Leydig, Leiirb. d. Ilistologie, p. 201 and Festsctir. z. Feier d. lOO-juhr. Best. d. Naturj. Ges. :. 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. 



marked with dm-k dots, wliiili are set in rows on the 

 raembi'ane between the rays. On the back too tliere 

 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 sjjinous rayed part, which also in- 

 creases proportionally in the same way, forms about 

 7s of the fin. Both tlie spinous-rayed and soft-rayed 

 parts — the depi'es.sion between which recalls to mind 

 the two separate dorsal fins in the Perch and Pike- 

 perch — have a rounded (convex) margin; and in l)oth 

 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 reallj- corresponds to the first I'ay 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 l:)ack; it is o^■al 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, wliich are larger in the Pope 

 than in tlie 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- 

 trachians-^. The orifices of these ducts form, in the case 

 of the Pope, the so-called muciferous cavities, which 

 are lined with a membrane which fi-eely secretes the 

 mucus. There are three of these oval cavities on the 



