380 



SCANDINAVIAN FISHES. 



ill front of the first niuciferous cavity of the dorsal 

 margin; and the anterior nostril lies obliquely above 

 the posterioi', which has the form of a slit, but is so 

 obliquely set that it is almost parallel to the dorsal 

 margin of the head. The eyes are fairlj^ large. Tlie 

 longitudinal diameter of the upper orbit measures nearly 

 lialf the length of the cranium from the head of the 

 vomer to the occipital foramen; and the longitudinal 

 diameter of the eyes themselves (the upper eye is some- 

 what larger than the lo-\ver), measured within the der- 

 ma! folds that serve as eyelids, is about ^'^ of the total 

 length of the head. Half or a third of the upper eye 

 lies behind the perpendicular from the hind margin of 

 the lower. The mouth is small, the length of the 

 maxillary bones varying between about 3 and 3' 2 ^" 

 of that of the body, and the length of the lower jaw 

 between about 5 and 6 %'' thereof. The transverse 

 palatal folds are well-developed, though not large, both 

 in tlie upper jaw and the lower. The loAver jaw is 

 furnished with a well-developed chin protuberance under 

 the symphysis. The lips are fleshy, but not tumid. 

 The jaw-teeth, which are jjointed in young specimens', 

 subsequently become chisel-shaped. The gill-rakers are 

 well-developed but scattered, and set in a single row, 

 containing about 8 on the first branchial arch. On the 

 lower phai-yngeals, which are narrow and long (like 

 liranchial arches), these spines are exchanged for a double 

 row of conical, obtusely pointed teeth. The roof of the 

 palate, as usual, is truncate posteriorly, with a deep 

 ])liaryngeal cavity behind it, into which is titted tlie 

 upper ])haryngeal apparatus, consisting of three jiairs 

 of iiharyngeals directed outwards and backwards, each 

 with a row of six or seven conical teeth. The tongue 

 is small and narrow, but the hyoid surface (copuhir 

 part) is continuous and fleshy, widening into a triangle 

 behind. Tlie pseudobranchia} are set just behind the 

 upper articulation of the hyoraandibular bones, at the 

 extreme front of the pharyngeal cavity mentioned above. 



The preoperculum of the eye side is more obtuse-angled 

 than that of the blind side, the latter being also fur- 

 nished with broader margin and much larger muciferous 

 cavities. The operculum forms an almost equilateral 

 triangle, as in most of the Flatfishes, with the hind 

 upper corner rounded and the lower posterior margin 

 incised. The suboperculum is as usual elongated back- 

 wards and upwards to a point, which fills this incision, 

 the suboperculum thus forming the greater part of the 

 hind margin of the gill-cover, u]) to the obtuse flap of 

 this margin. The interoperculum is attenuated anteriorly. 

 The branchiostegal membranes are as usual free, but 

 inferiorly united to each other in a broad transverse 

 fold, Avhere the tips of the first two branchiostegal rays 

 touch. In ordinary cases this transverse fold covers 

 the point of the clavicular bones; but when the gill- 

 cavity is strongly expanded, the fold is drawn so tight, 

 into the angle of the urohyoid bone, that the point of the 

 clavicular bones is externally visible as a forward process''. 

 The dorsal fin begins above the middle or the front 

 of the upper eye, exactly at the dorsal margin or with 

 the first ray alone slightly drawn over towards ihe blind 

 side, and extends back to a point the distance between 

 which and the caudal fin is aliout half the diameter of 

 the eye. The dorsal fin is evenly rounded, the longest 

 rays being situated at the middle of its length, and 

 their length being aliout equal to the vertical height 

 of the preoperculum. The anal fin, which begins be- 

 hind the anal spine, a little l)ehind the perpendicular 

 from the insertion of the pectoral fins and below the 

 16th, 17th, or 18th ray of the dorsal fin, at a distance 

 from the tip of the snout that measures about 19 — 24 

 % of the length of the body, is of the same shape and 

 height and ends in tlie same manner as the dorsal fin. 

 All the rays in the dorsal and anal fins are simple', 

 articulated, and undivided. The pectoral and ventral 

 fins are pointed, seein generally to be longer in the 

 males than in the females', and are ahvays somewhat 



" On tlie blind side, according to our measurements, at least 3-3 % and at most 3-7 %, on the eye side at least 2'9 % and at most 3-4 %'. 



'' On tlie blind side, according to our measurements, at least 5-3 % and at most S'O 'i, On tlie eye side at least 4-7 \ and at most 5'6 %. 

 On the blind side we have found the Icnglh of the lower jaw (in specimens between 378 and 51(1 mm. in length) to vary between 81 '/o and 

 84Vo''» of the least depth of tlie tail; on the eye side between 72 and 83 °i thereof. According to Kroyer's measurements, however, the last 

 proportion may be as low as CC'7 ?». 



'■ "Conical and separated:" Goonic and Bean, 1. c. 



'' The urohyoid bone is united by a long ligament to the hyoid bone, but is closely joined to the clavicular bones. 



'' "Sometimes," says GoTTSCHE, however, "the last rays of the dorsal tin are branched." 



•' In three males, between 378 and 516 mm. long, the minimum length of the pectoral fins was 9-2% and the maximum 12-6% of 

 the length of the body, while in the case of the ventral fins these proportions were respectively 5'5 and 7'2^i. In three females, between 

 418 and 470 mm. long, the minimum length of the former fins was l-<S'/o and the maximum 8'8 °i of the length of the body, while in the 

 case of the ventral fins these jiroportions were respectively 5 and 5"1 %. 



