1080 



SCANDINAVIAN FISHES. 



is sliared by the ]iu|)ils. At tlie anterior iiiar<rlii of 

 the eyes the t'oreliead of tlie. females is soniewliat tumid, 

 and in tlic males tlie coiTesponding prominence is me- 

 dially concave; but behind the concavity articulates the 

 singular hooked organ (fig. 294, If) whose jn-obable 

 function as a prehensile organ during copulation we 

 ha\i' iilrcady pointed out. It is a curved rod of 

 hard cartilage, the base of which is widened and pro- 

 more — is occupied by the prolongated tail', which is : longated, gliding by means of a longitudinal articulary 



Chiuuera horealis, SilAW, Geiier. Zool., vol. V. pari. I, p. 30.'), 



tab. 157. 

 V/iiincera arctica, Hoi.lb., Boliiml. Fisk'., fasc. II, \>. 1 uuiii 



tab. (Gbgs Wett., Witt. Sainli. N. Hand!., part. IV). 

 Chima-ra mediterranea, Risso, Eur. Mei:, torn. Ill, p. 108. 

 (.')Cln'ma'ra phtmbea, Gill, Proc. Philos.Soc. Washington, Dec. 2'2, 



1X77; vi(k, .lojtD., GiLi!.. Bull. U. S. Xat. Miis., No. 10, p. :,i. 



The Nortlu'iMi (-liima.'ra attains a lengtli of about 

 a metre". The greater part of tliis length — " ., or 



thread-like at the tiji. Tlie gi'eatest depth, just beliind 

 the pectoral fins, measures \'g — \!-, of the length; and 

 the greatest breadth (thickness), just in front of the said 

 point, is about '/a — % of the greatest depth. Where 

 the first dorsal fin is situated, the dorsal line is straight; 

 from tills part it slopes at an angle of about 4r>" to- 

 wards the snout, but very slowly towards the tip of 

 the tail. The inferior profile of the head ascends from 

 behind about as much as the upper profile descends or, 

 when the mouth is open, a little more; but the belly 

 is usually rounded and tumid, the inferior caudal profile 

 (behind the ventral fins) thus ascending in a very gra- 

 dual curve. The l)ody is, however, so loose and slippery 

 that no constancy in these respects can be e.Kpected. 

 The length of the head, which is conical and be- 

 hind laterally compressed, decreases as usual during 

 growth, varying between l.'i and 11 % of that of the 

 body in specimens 7 — 9 dm. long. Its most charac- 

 teristic features, the position of the mouth and nostrils, 

 as well as the structure of the soft and somewhat trans- 

 lucent snout, have already heen descrilied. The longi- 

 tudinal diameter of the large and ovally rounded eyes 

 in the specimens just . mentioned measures about ^/^ 

 (37 — 31 %), and their vertical diameter about '/j (22 

 — 18 %), of the length of the head. They are .set high, 

 their superior margin lying but slightly below the frontal 

 profile, but somewhat obliquelj^ sloping in a forward 

 direction; and whereas the length of the snout in front 

 of them measures about '/^ (48 — 51 %) of the length 

 of the head, the postorbital length of the head is not 

 much more than Vs (35 — 38 %) of its entire length. 

 The elongated form is not re.stricted to the orbits, but 



gi-oove on tlie median edge of the forehead, and the 

 top of which is furnished on the under surface with 

 a card of 40 — 50 pointed, recurved teeth. As the 

 form of the articulary surface shows, the hook is only 

 slightl}' erectile; but when it is depressed, the card 

 of teetii works against the anterior ]);irt of the said 

 prominence. 



On the external surface of the snout the Northern 

 Chinian-a accjuires one of its most characteristic singu- 

 larities, consisting in the ramifications of the lateral 

 line. The lateral line itself extends, as usual, along 

 the sides of the body, in front rather high, behind 

 nearer to the middle of the sides, until it descends just 

 behind the beginning of the lower caudal lobe to follow 

 the base thereof. It is without true jiores, liut instead 

 has a fissure-like opening throughout its lengtii, this 

 being due to the structure of its wall, as first descril)ed 

 by Leydig'. Instead of piercing through scales, which are 

 wanting in these fishes, the wall of the lateral line is sup- 

 ported liv half-rings'' set beside eacli othei' and branched 

 at the tops. In this form the lateral line advances on 

 the head, where it runs upwards and inwards' on the 

 occiput, and just behind the mouths of the aqiKediictus 

 vesfihidi sends out a transverse canal', a line of commu- 

 nication between the two sides of the body, with a 

 backward offshoot in the middle. Forward from this 

 transverse canal a supraorbital branch'' runs on each 

 side of the head, above the eye and latei'ally along the 

 bridge of the snout, to the side of the tip of the snout, 

 where it bends downwards and backwards, though only 

 to meet and join in a curve on the under surface of the 

 snout the supraorbital branch of the opjiosite side. A 



long. Tbe true lenglli of (lie 



" Day and Lilljeborg give 4 feet (1,200 mm.). Our largest specimens are females about 95 

 body is in many cases doubtful, for it is difficult to see whether the tip of the tail is entire or broken. 



' Our specimens corroborate Lilljeborg's statement that the males have the comparatively longest tail; but Krover's measurements 

 show the reverse, and rather indicate that young Chimserae have a comparatively longer tail than old. 



"■ Arch. Anat., Physiol. 1851, p. 251, taf. X, tigs. 2 and 9. 



'' Of an osseous structure, according to Leydig. 



' This ascending portion is called by Garman (Bull. Mus. Comp. Zool. Harv. Coll., Cumbr., vol. XVII, No. 2) the occipital canal. 



.' Aural canal, according to Garman. 



•" Cranial canal and rostral canal, according to Garman. 



