584 



lliiu osseous rid^ires, nnd projects iiKire or less l)eyoud 

 tlie inontli, wliicli is forced di)\\nw.-inls in ilie lower 

 surface of tlie head, like tliat of a shark. Tlius, great 

 as the dissiuiilaritv is hetweeu the extreme forms of 

 the snout in the species of Macrurus, there is no funda- 

 mental difference in structure; they merely represent 

 different degrees of the same line of modification. 



"With regard to the scales, tiiere is alsf) every 

 gradatinn from the small-scaled ]\IaIarocej)Iinli to the 

 large-scaled Macnirus Umgiharbis. In very young spe- 

 cimens of all species the scales formed at first are al- 

 ways thin, witlioiit am- armature, in fact c-scloid. Spines 

 apj)ear only after some time, generally in the median 

 line of the scale, simply and not in series; .scales with 

 fully develope<l armature are generally not found in 

 specimens under <S inches in length. In some species 

 • which normally possess strongly spiniferous scales, 

 individuals may occur (esi)ecially such whose skin is 

 wanting in pigment), in which the spines are much 

 more feehle and scarcely visible. And finally, there 

 are species in which the cycloid structure of the scales 

 remains normally persistent. Tims, neither the size 

 nor the structure of the scales can he safely used as 

 a generic character." 



On the other hand, GCntiikk fully recognises the 

 validitj' of a character first suggested for this piirpose 

 by LCtken", and derived from the presence or absence 

 of the spines (set in an upwai'd (backward) direction 

 on the front surface of the I'ay) that arm the second 

 (apparently the first) ray of the dorsal fin. Even this 

 character is subject to changes of groAvth, for, where 

 these spines are present, in old specimens they may 

 Ijecome indistinct (tubercular); but they never dis- 

 a])pear altogether. 



The species hitherto disco\ei-ed \\ithiii the limits 

 of the Scandinavian fauna may be distinguished, ac- 

 cording to these opinions, in the following manner: 

 A : Jaw-tccth at least in front cardi- 

 form (or velvet-like); scales middle- 

 sized or large. 



1 : Snoutpointed;cheekscarinatcd : 

 a; Second ray of the first dor- 



sal fin smooth (unarmed)... J ''^"'•'■"'■"■' ('-'o''lorh>/nrh,„) 

 I coelorhynchus. 



.SC.\NI)1NA\1A\ I-ISIlIiS. 



/).- Second rav of the first dor- 



sal fin spiny I ^tan-nru, {Macruru,) 



■2: .Snout blunt; cheeks almost' Fabncii. 



lMa<;ni7->(s {Cort/phmnoides) 



B: Jaws furnished with canine teeth ^ rupestris. 

 set in two rows in the upper jaw. 



in one row in the lower I •""'■'•'"■"•^' (Malwo- 



I ri'phahis) hrris. 



It sometimes happens, however, that the character 

 derived from the structure and arrangement of the jaw- 

 teeth, employed in this maimer, firstly brings together 

 forms extremely dissimilar in otlier respects'', and 

 secondly is very difficult of employment, for in young 

 specimens of the (.'orypha?noid group, even when they 

 are 12 cm. long, it is hardly possibly to discover more 

 than two rows of teeth in the upper jaw and one row- 

 in the lower. Again, several s}iecies of Glnthers sub- 

 genera Chalinurits and OpfointrKS have true canine teeth 

 in the outermost row of the card in the upper jaw and 

 only one row of teeth in the lower jaw. The followitig 

 classification appears easier and, therefore, more trust- 

 worthy. 



A: Least breadth of the intcrorbital 

 space less than the length of the 

 snout, than ^j^ of the length of 

 the head, or than ^,5 of the greatest 

 bread til of the head at the perpen- 

 dicular from the centre of the eye: 

 a: Least breadth of the intcrorbital 



space more than or equal to ',, 



of the length of the lower jaw, 



which is less than 40 % of the 



length of the head. ,\fai'rur!i!< coelorliipichus. 



b: Least breadth of the intcrorbital 



space less than '/o the length 



of the lower jaw, which is more 



than 40 % (44 %?) of the length 



of the head Macnirus Fabricii. 



B: Least breadth of the intcrorbital 

 space greater than the length of the 

 snout, and greater than orequalto V3 

 of the length of the head or ",q of 

 its greatest breadth at the perpen- 

 dicular from the centre of the eye. 

 a; Least breadth of the intcrorbital 



space more than ''/. of the length 



of the lower jaw Macrurus rupestris. 



h: Least breadth of the intcrorbital 



space less than or equal to ^/j 



of the lenoth of the lower iaw Macrurus hecis. 



" Vi.l. Medflel. Natnrli. l^c.r. Kblivii 1872. \.. 4. 



'' Of., for example, Mucnirus licvis and Macnirus macrochir. 



