GREAT WEEVER. 



129 



from tlie iiortli of the Sound off tlie fishing-village of Molle, wliich 



is clearly an intermediate form between the supposed species last 



mentioned. Its length is 237 mm. There are 6/2S rays in the 



2 

 dorsal fin and ,- - in tlio anal. The greatest depth of the bo.ly is 19 "i 



of the length — in the deepest typical specimen of Tr. draco tliat 

 I have measured, it was 17.3 %. The least depth is G.3 % of the 

 length and 13.3 % of the second dorsal fin; in typical specimens of 

 Tr. draco it is at most 5.9 'i and 11.9 K respectively. The length 

 of the base of the second dorsal fin is only 47.7 °i of the length of 

 the body; in typical specimens of Tr. draco it is at least 49.2 %. 

 The length of the lower jaw is 13 "» of the length of the body, 

 53.9 % of the length of the head, and 27.4 % of the length of the 

 second dorsal fin : tlie highest corresponding ratios I have found in 

 typical specimens of 'Tr. draco are 12.4, 52.4 and 24 respectively. 

 Above the anterior corner of each eye there are 3 spines; in per- 

 fectly typical specimens of Tr. draco I have never found more than 

 2. As far as I can judge frojn six measured, typical specimens of 

 Tr. draco, 3 cf and 3 9i however, it is most correct to regard this 

 intermediate form, though a o" specimen, as being, in most of these 

 peculiarities, the result of an abnormal development of the external 

 female characters. — Cf. with regard to the influence of the sexual 

 characters on the development of form in the Salmonoid family, Smitt, 

 Eiksmuseets Salmonider, Vet.-Akad. Hand!., Vol. XXI, No. 8, pp. 

 204, 289, and several other passages. 



The body of the great Weever is long, compressed, 

 and thickest at the top of the head, but even there 

 the greatest thickness i.s only Va of the greatest depth 

 of the body. The length of the head varies between 

 21 and 24 % of the length of the body. The longi- 

 tudinal diameter of the ej'es in j^oung specimens until 

 about 250 mm. long, is between 21 and 20 % of the 

 length of the head; in older specimens it is between 

 18 and 17 %. The scales of the body are oblong and 

 set in very distinct, parallel, transverse roAvs, which 

 run obliquely downwards and backwards, and are about 

 80 in number". The cheeks, temples and operculum 

 are covered with very small scales. The nostrils are 

 small and situated above the preorbital bone: the an- 

 terior, which is the larger, has a grooved flap in the 

 posterior margin; the posterior looks like a slit. The 

 first three spinous rays in the first dorsal fin are fairly 

 close together at the roots, the last three farther apart. 

 The second or the third ray is the longest. We may 

 sometimes find one or two of the rays longitudinally 

 (sagittally) divided from in front. The fin Yn&y be 

 hidden in its groove, but also admit.s of being sharply 

 raised, so that the first ray points somewhat forward. 

 The second dorsal fin, like the anal, which is still longer 

 than it, is fairly uniform in height: the rays of the 

 latter fin are thick and covered with a .skin, which 

 projects at the side almost like a flap. The caudal fin is 



" In the lateral line their number is from 77 to 85. 

 Scandinavian Fishes. 



truncate or only slightly concave. The pectoral fins 

 are truncate, with If) or Hi rays, tin; two ujjpermost 

 being generally .simple, the next 8, 9 or 10 (juadrifid, 

 or the last of them deeply bifid, and the last 5 or 6 

 thicker and bifid at the tip, or the lowest ones simple. 

 In the axil is a broad dermal flap, which is scaleless, 

 but in other respects resembles the structure which 

 exists at the same spot in Brama (see above). The 

 ventral fins are set close together and small, measuring 

 between 8 and 10 % of the length of tlie bod}'. The 

 lateral line i.'< almost perfectl)- straight and runs nearer 

 the back than the belly, but slopes .somewhat down- 

 wards at'-the base of the caudal fin. 



The Great Weever is adorned with fairly bright 

 colours, which in a strange way shift into one another 

 in the form of broken, oblique, narrow bands. The 

 first dorsal fin is dark in front, with den.se, large, black 

 spots and reddish brown rays, and light behind. There 

 is a dark spot on the anal fin too, near the ninth ray. 

 The posterior dorsal, the colour of which, with the 

 exception of the spot, is reproduced in the anal, is 

 whitish at the base, with a yellow .stripe along the 

 middle, and edged with blue. For the other details of 

 the coloration we may refer to the figure. 



As the abdominal cavity is fairly small, though it 

 extends even behind the vent, the digestive canal lies 

 in spiral coils. The stomach small, but fairly thick 

 and firm. Six pyloric appendages. The liver consists 

 of two lobes, the left considerably larger than the right, 

 to which the gall-bladder is attached. No air-bladder. 

 The urinary bladder long and fairly narrow. The 

 generative organs are situated in the posterior part of 

 the abd(jminal cavity. The dorsal column consists of 

 40—42 (10 or 11-1-30 or 31) vertebra-. 



No external difference between the sexes in this 

 species is yet known. Though Costa states that the 

 male has only 5 spinous rays in the first dorsal fin, 

 while the female has 6, this difference, in Sweden at 

 least, does not hold good. In the females, however, 

 as a rule, the head seems to be longer and the distance 

 from the middle of the tip of the snout (which is some- 

 Avhat concave, as the preorbital bones project forward) 

 to the beginning of the dorsal fin so much greater than 

 in the males, that in 3 females and 4 males we have 

 found the length of the lower jaw, without exception, 

 j in the former less, in the latter more, than 63 % of 



17 



