1 1 50 



SCANDINAVIAN FISHES. 



The head occupies about 17 (I?',,,) — 15 (14'8) % 

 of the length of the hody, and differs essentially from 

 that of the following genus in the length of the snout, 

 wliicli measures nearly half (49V2 — 46 %) of that of 

 the liead. Tiie snout is translucent, and its skin is 

 pierced with nuinei'ous ampullar orifices, arranged above 

 in series so as to form oblong patches on each side of 

 tlie median line, below in the manner illustrated in 

 fig. 334. The nostrils, wliicli are directed obliquely 

 inwards and backwards from the edge of the snout, 

 have the anterior overla])])ing margin double (cf. above, 

 im the To])e), and the outer lobe (/we) has a pointed 

 tiiangular Ha]), tlie base of which is continued inwai-ds, 

 the inner (/(//) an obtuse, more or less rounded flap, 

 belonginir to tiie outer jiart of the nostril. Exactly 

 opposite the last-mentioned flap there projects a more 

 deep-seated, more tubercular lobe (Jpe) fi'om the pos- 

 terior margin of the nostril. In this manner the nostril 

 is incompletely divided, as that of the Ravs, into nn 

 outer (anterior) and an inner (a posterioi') part; but 

 the latter is not confluent either with the nostril of 

 the opposite side or with the mouth. The distance 

 between the inner ends of the two nostrils is .somewiiat 

 more tlian '3 (in the younger among our specimens 

 about 3(i %, in the older about 34V2 %) of the length 

 of the snout; and the distance from either of these 

 ends to the mouth varies between '/, and ^/j of the 

 former distance. The orbits are oblong, the vertical 

 diameter being about "/s of tiie longitudinal or even 

 less, and the longitudinal diameter measuring about 

 half tlie length of tlie snout, somewhat more or less, 

 or about "/g of the interorbital width. Exactlj' behind 

 the orbits — at a distance from them rather greater 

 than their length — lie the spiracles, whose diameter 

 is about ','4 of tliat of the former. The mouth is semi- 

 circular, the lower jaw being somewhat more pointed 

 tlian the upjier, and is so situated that the anterior 

 margin of the upper ja^\• lies in a line witii tlie |n'e- 

 orbital margin or a little behind the perpendicular there- 

 from, the tip of the lower jaw almost below the centre 

 of the eyes. Lips are wanting, but the corners of the 

 mouth arc elevated and posteriorly bounded by a rather 

 deep semicircular groove. The teeth are pointed, with 

 one or two lateral denticulations on each side of the 

 main cusp. They are set in a quincunx of three — live 

 series, which gives them the appearance of being dis- 

 triliuted in some thirty longitudinal rows running 

 obliquely backwards and outwards across the jaws. The 



tongue is fleshy and flat, as in most of the Sharks. 

 The gill-openings are middle-sized, the hindmost being 

 .set above the beginning of the pectoral flu. 



The dorsal fins are characterized, as in the follow- 

 ing genus, by their similarity to each other both in 

 form and size; lint in these fins, as in tlie other un- 

 paired fins, it siiiiuld lie ol)serve(l that the forward 

 extension of the anterior margin varies in different in- 

 dividuals, the measurement of the basal length being 

 thus rendered uncertain. The distance from the tip of 

 the snout to the first dorsal fin is about 45 (44'/2 — 

 47' 2) %, to the second about 63 (62—64) %, of the 

 length of the body; the interval between the two fins 

 measures between 13 and 14 % of the said length. 

 Their form is obliquely quadrilateral, with the jiosterior 

 corner almost rectangular. The length of their base 

 varies between 4 and 4' „ % (sometimes nearly 5 %), 

 and tiicir liciglit l)etween 5 and 6' 2 "o, of the length 

 of the bod}'. The first dorsal fin lies opposite to the 

 anterior part of the space between the ventral and anal 

 fins, the second to the posterior part of the anal fin. 

 The last-mentioned fin, which has an unmistakable re- 

 semblance to the anterior part of the lower caudal lobe 

 (an obliquely trapezoidal form, gradually attenuated 

 behind, with pointed infero-posterior corner and slightly 

 concave under margin), is here distinguished by its 

 length — about 15 — 16 % of that of the body, and in 

 the females 4 times or less, in the males u|) to 5 times 

 the greatest height of the fin. The distance between 

 the tip of the snout and the beginning of the anal fin 

 measures in full grown females perceptibly more than 

 '/b (about 54 %), in males and young females about 

 ','2 or less (49—51 ?»), of the length of the body. The 

 caudal fin is expanded at the end, obliquely truncate, 

 with somewhat rounded corners. Its length from the 

 beginning of the anterior lobe is inoix' than ''4 (27'/j 

 to nearly 33 %) of the length of tiie body. 



The pectoral fins are broad, obliquely truncate, 

 ■with rounded corners. Their length at the anterior 

 margin varies between 10 and 12' 2 *» their base be- 

 tween 6'/ 2 :tnd 8 %, of the length of the body. The 

 ventral fins are quadrangular, low but long, with the 

 posterior corner pointed. Their base is longer than that 

 of the pectorals — in the females about 8' 2 %, in the males 

 about 9 %, of the length of the body — but their iieight 

 (breadth) is only about '/g or ^ '^ of the length of the base. 



The lateral line is quite distinct, from the very 

 temples, and at first runs about half as far from the 



