534 



SCANDINAVIAN FISHES. 



the eve, and its length nieasuves from D^A, to a little 

 more than 11 % of that of tlie body or from 47 to 

 54 % of that of the head. In front it is a little shorter 

 than the upper ja\\'. Tlie teeth are rather close-set, 

 tine, and pointed, and form a broad, cardiform vow on 

 the intermaxillary bones and in the lower ja^v, ^vhile 

 on tiie head of the vomer they are set in a semicircular 

 l)an(l. The palatine bones are toothless. There are no 

 transverse folds (vela) within the mouth. Tiie four jjairs 

 of branchial arches are furnished on the inside (in front) 

 with a double row of tubercular, ])nt onh- few gill- 

 rakers, 5 — 7 on the first arch. The cards of pharyngeal 

 teetli, the upper ones united into a roundish patch on 

 each side, are composed of densely set, small teeth, and, 

 here as in the preceding genus, we find a small patch 

 of teeth on the third pair of cpibranchial bones. The 

 branchiostegal membrane is extended by seven large 

 and thick, but only slightly flattened ravs. It lies bare, 

 is rather large and onlv slightlv, if at all, incised at 

 the middle (under the isthmus), where it forms a broad, 

 free fold right across to the opposite side. The gill- 

 openings ai-e fairly large. The tongue is large and 

 fleshy. 



In front of the vent the body is terete, and the 

 lielly more or less pendent; behind it strongly com- 

 pressed laterally and shallower. The hind part of the 

 anal aperture is situated at the middle of the length 

 of the body, excluding the caudal fin, and the usual 

 depth of the body at this point is about ^ ,; of the 

 length to the tip of the tail. The least depth of the 

 l)odv, at the base of the caudal fin, is l)et\veen about 



(sometimes 4) and 5' 



of the total lensfth of 



have soft, l)i'auched, ^vell-se})arated ravs, clothed -witli 

 a firm, thick skin, ^vhich is furnished with fine scales. 



The first dorsal fin generally begins at tlie end of 

 the first third of the total length of the l)ody, and 

 above the tip of the pectoral fins when laid l)ack. The 

 distance between it and the tip of the snout, ^\•hich 

 usually varies between 31' ^ '"i^^ 34 '/^ % of the length 

 of the body, may sometimes be as much as 37 V2 ^ 

 thereof (cf. above, Ohs)). It contains generally 13, 

 seldom 10 or 11 or even 15 or 16 rays, most of which, 

 at the middle of the fin, are of equal height, measur- 

 ing in most cases about \,j or 'A, of the greatest depth 

 of the body, but sometimes even more than ' ., thereof. 

 The anterior and posterior rays are variously shortened, 

 the latter sometimes missing. The incision which se- 

 parates the two dorsal fins, usually goes right down to 

 the back, and ^vhen the number of rays in the first 

 fin is extraordinarily small, this is due to the absence 

 of one or two ravs at its termination. The length of 

 the base of the first dorsal fin is about 8 or 9 % of 

 that of the bodv, though it may sometimes siidv to 

 about 6 % thereof. The second dorsal fin is of uni- 

 form height and generally somewhat higher than the 

 first. In most cases it contains about 75 rays, the first 

 2, 3, or 4 and the last 4 or 5 diminished in length. 

 The distance between the fin and the tip of the snout 

 varies between about 40 and 43 % (sometimes 46 %) of 

 tlie length of the body, and the length of its base be- 

 tween about 45 and 47 % (sometimes 42 or even 41 %) 

 of that of the body. 



The caudal fin is divided from the dorsal and anal 

 fins bv an incision in the membrane, but in j'oung and 



the body or about 22 (sometimes 20) and 28 % of the middle-sized Burbot the notch never extends down to 

 length of the head. The sharper convergence of the | the body, and in these specimens no distinct finless 



dorsal and ventral profiles, which proved in the Hake 

 to coincide with the beofinnino: of the hindmost sections 

 of the dorsal and anal fins, in the Burbot does not ap- 

 peal- until we reach the Itegiuning of the peduncle of 

 the tail, and is sometimes almost imperceptible. The 

 hiteral line, which is broad and distinct, but onlv sHghtly 

 depressed and often interrupted, I'uns from the sides of 

 the occiput, in a slight curve, near the back, approaches 

 the middle of the sides behind the vent, and advances 

 in a straight line to the tip of the tail. All the fins 



space (peduncle of the tail), at the dorsal margin at 

 least, is ever to be detected. It is first in a Burbot 

 of unusual size (age), 9 dm. in length, that we have 

 found the peduncle of the tail distinctly marked above 

 and below. When the fin is strongly expanded (as in 

 the figure), it is perfectly round; but it is generally 

 seen in a somewhat folded position, and is then oblong 

 and rather pointed, as in the Eel. It contains about 

 41 rays, of which 5 or 6 above and below are shortened 

 (supporting ra}s), Ijut not so transformed as in most 



" One (if the Royal Museum specimens from Lake Wetter, with comparatively large head, is further distinguished by the extraordinary 

 development of the fins: the height of the first dorsal fin is 9-7 °i, the height of the second dorsal fin 9-3 %, the height of the anal fiu 6.2 %, 

 the length of the pectoral fins 21-4 K. the length of the ventral fins 18'2 '/>, and the length of the middle rays of the caudal fin 9-1 % — 

 in each case, of the length of the bndy (483 mm.). 



