458 



SCANDINAVIAN FISHES. 



Nalnrv. Christ., Bd. 2!) (1884), p. 101: Lili,i., Sv., Nnrg. 

 Fn., Fish:, vol. 2, p. ?,50. 



Pleuronectes hirtiis, Abilik;. apiul MCll., Zool. Dan., vol. Ill, 

 p. 36, tab CIII; Retz., Fn. Stiec. Lin., p. 333; Nilss., 

 Prodr. Ichth. Sca?uL, p. 59; Gottsohe (Zeugoptenis), Wiegni. 

 Arch. Natiirg., I, 2, (1835), ji. 178; Friks {Pleuronectes), 

 Vet.-Akad. Haiidl. 1838, p. 184; Y auk (Ehoiabiis), Brit. Fish., 

 ed. 1, vol. If, p. 243; Parn., Mem. Wern. Soc, vol. VII, 

 p. 370; Kr., Danm. Fiske, vol. 2, p. 445; Nll.ss., i>l-and. 

 Fn.. Fi.-<1\. p. 04 G; MoK., Hist. Ant. Poi.9S. Fr., toio. Ill, 

 p. 321. 



.^^ll!lel■•.■^ Topknot, CnUCH, F?W/. Brit, hi., vol. Ill, p. 170, 

 tab. CLXV. 



Mollev's Topknot nttains ;i length of about 25 cm. 

 Tlie body is elliptical and of more uniform dejjth than 

 in the preceding genus, the greatest depth of the body 

 remaining almost unchanged for some distance, about 

 half-way between the tip of the snout and the caudal 

 Hn. The depth at this spot varies, at least after the 

 tish has attained a length of 90 mm., between 46 and 

 51 % oi the total length of the body, the proportion 

 i"i.sing fairly regularly with age. In front the body is 

 almost semicircular, behind more elongated, the least 

 depth (across the peduncle of the tail) varjang between 

 (j'/g and 8 % of the total length of the body, and 

 also increasing, even relatively, with age. The form 

 of the body is most affected, however, by the dorsal 

 and anal hns, which increase in height posteriori}', while 

 the depth of the body itself diminishes. When these 

 tins are taken into account, the I)ody is deepest at about 

 the l)eginiiing of the fourtli (piarter of the distance be- 

 tween the tip of the snout and the base of the caudal 

 tin. This depth is about 66 or 68 % of the total length 

 (if tlie body. The greatest thickness of the bodv in 

 old specimens is distinctly greater than in the pre- 

 ceding genus, increasing with age from about 8 to 9 % 

 of tlie lengtli of the body. 



The most remarkable |»oint in the form of the head 

 is tlie sharp ascension of the cleft of the mouth. When 

 tlie mouth is closed, the jaw-bones, at least the maxil- 

 laries, assume an almost perpendicular position; but the 

 nioutli is also highly protrusile, much more so than in 

 tlie ])receding genus. The intermaxillar^• bones may 

 be shot forward for a distance equal to the length of 

 the snout proper; the lower jaw is then horizontal, the 

 branches of the intermaxillary bones ])lace them.selves 

 at right angles to it, and the lower end of the maxillary 

 bones is directed obliquely forward. The jaw-bones are 

 fairly symmetrical, those of the eye side being only 

 slightly longer than those of the blind side, or etpial 

 to them in Icngtli. Just as the head as a whole is 



comparatively larger than in the preceding species — its 

 length undergoes even relative increase, during the 

 growth of the tish, from 26'/., % to rather more than 

 28 % of the length of tiie bodv — the jaws are also 

 even relatively longer than in Ekstrom's Topknot. The 

 length of the liranch of the lower jaw on the blind side 

 increases with age from about 12 to nearly 14 %, that 

 on tlie eye .side from 13 to a little more than 14 %, of 

 the length of the body; and the corresponding alterations 

 in the maxillary bones are from about lO'o to 12Vo % 

 (sometimes nearly 13 %) of the length of the l)ody. 

 The length of the lower jaw, ho^\•evel•, is always less 

 than that of the head ])ehind the lower e}'e, which in- 

 creases with age from about 14' 2 to 16' ^ % of the 

 length of the body. The eyes are fairly large, their 

 longitudinal diameter relatively decreasing during growth, 

 from about 38 '/^ to 25 72 ^ of ^'^^ postorbital length 

 of the head; but they are comparatively smaller than 

 in either of the two preceding genera. Their position 

 in relation to each other continues to change at a late 

 period in the growth of the tish: when the tish is 17 

 cm. long, we inav find the eyes still almo.st abreast of 

 each other, while in specimens 2 dm. long the wander- 

 ing (originally the right) eye ma}' have retired half its 

 diameter behind the lower eve. There is no intruding 

 lolie from the iris into the pupil: l)ut the rough skin 

 that covers the inner (in the lower e^•e the upper, in 

 the upper eye the lower) part of the eye, projects in 

 a more or less arcuate form out over the pupil. The 

 interorbital space is not remarkably broad in comparison 

 witli its breadth in other BofhiiKE, but it is broader 

 than in the two preceding genera, its least breadth va- 

 rying in this species between 30 and 45 % of the lon- 

 gitudinal diameter of the eye. It is only on the eye 

 side that the nostrils are always distinct, or at least the 

 anterior, with its foliate dermal flap. On this side they 

 are set close to each other, on about a level with the 

 middle of the iiit(n-orbital ridge, and the posterior just 

 in front of the perpendicular from the anterior margin 

 of the lo^ver e}'e. On the blind side the}- are extremely 

 small — where they are present at all — as fine as the 

 poi'es of the lateral line, and in most of our specimens 

 they are inipos.sible to detect in the loose skin that 

 covers the nasal cavity, just liehind the articulation of 

 the maxillary bone, below the second and third rays 

 of the dorsal fin. In one oi our specimens they are 

 present in the form of open, but extremely small holes, 

 in another thev are somewhat larger, but covered by 



