804 



SCANDINAVIAN FISHES. 



the Stjslntia Naturae. This is eviiicnt from the appended note in tlie 

 Fauna, where LlNN/EUS expressly states that he had counted 35 rays 

 in the anal fin of the Bjorkna — a nnnibei- which, among the species 

 indigenous to Sweden, is to be found in Abraiiiis hallevus alone. In 

 Retzics's edition of the Fauna Suecica the error was not corrected, 

 altlioiigh Bloch had already given a lucid description and a good 

 figure, considering the date at which it was executed, of Abtedi's 

 species, under the name of Ci/printts Blicca, which it still retains. 

 NiLSSON was the first Scandinavian writer to restore the name of 

 Bjorkna to its original signification, and to recognise Bloch's nomen- 

 clature (see Prodi: Ichtli. Scand.)\ but Ekstrom had previously (Vet.- 

 Akad. Handl. 1830) expressed the same opinion on the strength of 

 iiiforrnatioii privately sii|>plied to him by NiLSSON. 



Tlie \\'hite Breain is the smnllest Scaudiiiaviaii 

 member of the genus Abram'is. It never attains any 

 consideralile .size. Its ordinary length is between 1.") 

 and 23 em., rising, however, sometimes to 30 or, in 

 exceptional cases, 35 cm., including the whole of the 

 caudal fin. 



In most respects the \\ liite Bream comes nearest 

 our common Bream, and in apiiearance so closely re- 

 seml)les J'oung Bream that it is frequently confounded 

 with thera, under the common name of Braxenpan'ka. 

 In our description we shall therefore lay special stress 

 on the differences brought ti) light by a comparison 

 l)etween them. 



In the form of the body it is hardly possible to 

 detect any constant difference bet^veen the ^^'hite Bream 

 and the Bream. The bod}- of both is compressed and 

 deep, though generally a little less so in the former. 

 In White Bream preserved in the Royal Museum, and 

 measuring between 106 and 239 mm. in length to 

 the end of the middle rays of the caudal tin, the great- 

 est depth of the body is between 31 ?o (in young spe- 

 cimens) and nearly 40 % (in old) of its length, and the 

 greatest thickness (with more individual variations) be- 

 tween Vs and V4 of the greatest depth. The least depth 

 of the tail increases during these changes of growth 

 from 9-4 to 11-3 %. of the length of the body. The 

 back, which rises somewhat abruptly from the occiput, 

 tlien ascends in a regular curve to the beginning of 

 the dorsal fin, where it forms an ol)tuse angle, and 

 afterwards slopes almost in a straight line to the caudal 

 tin. Though (marinated from the occiput to the dorsal 

 tin, it is thicker and more conve.x than in the Bream. 

 The belly is flat from the jiectoral region to the vent- 

 ral tins. From this point to tlie \ent it is sharply 

 carinated. The ventral proiile is almost straight from 

 the pectoral region to the anal a])erture, where it forms 

 an obtuse angle, more acute, however, than the dorsal 



angle, and advances in a somewliat incurved line to 

 the caudal fin. ■ 



The head, the length of which is about ' , (21'/.,— ^ 

 20 %) of that of the body, tapers uniforndy forwards 

 from abo^■e and below, but the snout is fairly thick and 

 obtuse, projecting a little beyond the mouth. The fore- 

 head is broad and convex, the breadth of the inter- 

 orbital space being abotit 7' ., — 8 % of the length of 

 the body, or 35', ,—38', % of the length of the head. 

 The fi-ontal profile is straight from the occiput to the 

 nostrils, where it descends abruptly, and slopes towards 

 the snout. The sides of the head are moderately com- 

 pressed, the thickness being ecjual to the deijth, mea- 

 sured at the anterior orbital margin. The mouth is 

 small and ascends only slightly, but may be i)roiected 

 to some distance in a tubidar form. The corner of the 

 mouth falls short of the perpendicular from the anterior 

 orbital margin. The length of the snout, which mea- 

 sures about 5 — 6 % of that of the body or about 23 — 

 31 % of that of the head, is as a rule equal in young 

 specimens to the length of the upper jaw (from the tip 

 of the snout), in old a little greater. The length of 

 the lower jaw measures about 6' ^ — 7 ?» of that of the 

 body, or about 32 — 34 % of that of the head, is less 

 than that of the suture between the sul)operculum and 

 operculum, and also than 11 % (in the said specimens 

 70—57 %) of the least depth of the tail. The eyes, 

 on the other hand, are comparatively larger than in 

 the Bream, their longitudinal diameter varying in our 

 specimens between about 34 and 27 % of the length of 

 the head, while in young specimens it is perceptildy 

 greater, in old slightly less, than the length of the snout. 

 Their size is often so considerable tliat the \\'hite Bream 

 may be at once distinguished thereby from the young 

 Bream in its company. The position of the eye is such 

 that the postorbital length of the liead in young sjie- 

 cimens is less, in old somewhat more, than half its 

 entire length. The nostrils are set nuirh as in tiie 

 Zarthe, the distance lietweeii the posterior nostril and 

 the ui)i)er anterior part of the orbital margin l)eing 

 about " r, of that l^etween the anterior nostril and the 

 tip of the snout. The anterior nostril is smaller than 

 the posterior, but circular; while the latter is obliquely 

 set and elliptical or crescent-shaped. The gill-openings 

 are smaller than in the Ziirthe, the branchiostegal mem- 

 branes coalescing below with the isthmus at a greater 

 distance from each other and farther back, in a line 

 \\\i\\ the hind (vertical) margin of the preoperculiun. 



