K7' 



Its len;L(tli, wliicli sliows with f;iir tiniturniilx' even re- 

 lative increase with aue, Nai'ies hctweeii I'i' ., and Ki'/j 

 % of that (if the licidy, Ix'twccii about GO and 76 % of 

 that of ilie head, or between about 86 and 98 ?i of 

 that of tile liead reduced. Tlie nmutii and jiliarynx 

 witii tlieir dentitinn lia\e ali'ead\- ijeen destTibeci. Tlie 

 gili-i'id'iei's ai'e set in one I'ow of ;!4 — -Ti on tlie lirst 

 branchial arch, and are setif'ovni, fine, dense, and long. 

 The pseudol)ranclii:e compose a narrow, longitudinal 

 band on each side, made up of aliout Id short, trans- 

 verseh' set threads, just behind the boundary between 

 the jialatine arcli and the branchial cavity, and running 

 straight back from the upper insertion of the tirst 

 branchial arch. The operculum is (|uadi'ilateral, trape- 

 zoidal, with the upper margin shortest, the posterior 

 slightly concave at the top, and the inferior straight. 

 The length of the last-mentioned margin, which is di- 

 rected obliquely backwards and upwards as in the Sal- 

 raons. varies in different individuals between about 32 

 and 24 % of that of the head. The sidioperculum also 

 resembles that of the Salmons, being rather narrow but 

 of uniform breadth, and rounded at the lower posterior 

 corner. The interoperculum is triangular, most pointed 

 in front. The preoperculuni is rounded at an obtuse 

 angle. The gill-openings are large, extending up above 

 the middle of the superior opercular margin and down 

 to a level Avith the centre of the eyes. The branchio- 

 stegal membranes are broad and thick, free both from 

 each other and the isthmus; but at the extreme front 

 they cross, the left overlapping the right. The first 

 two (three) braiichiostegal ravs are slender, setiform; 

 the other five sabre-shaped, gradually increasing in 

 breadth liackwards (upwards). 



The dorsal fin begins at a distance from the arti- 

 cular knob of the maxillaries that inci'eases with age 

 from about 4t; to .")0 % of the length of the body. Its 

 base varies between about 7' .-, and (S7.., ?», and its 

 greatest height (the length of the 3rd or 4th ray) be- 

 tween about 14 and IJ %, of the length of the body. 

 Above it is obli(|uelv truncate, with the upper posterior 

 margin straight or somewhat convex. The adipose tin 

 is of the same shape as in the Salmons, but of a di- 

 stinctly fibrous texture. It is situated above the poste- 

 rior part of the anal tin, at a distance from the caudal 

 fin measuring about ' ,„ — ^^ (9' „ — 12' ^ %) of the 

 length of the l)od}'. The anal tin begins at a distance 

 from the articular knob of the maxillaries equal to about 

 70 % (69';.,— 72' , ?«<) of the length of the body, the 



ScauiUnnvmn fi.ihe!. 



percentage being generalh' greatest in the females. TIjc 

 length of its base \a.rics between 14 and 1 1 "*, and its 

 greatest height (the length of the 3rd — 5th ray) between 

 10 and 8' ., %, of the length of the body. Its inferior 

 margin is somewhat conca\'e. The caudal tin is deeph' 

 forked, the length of the middle rays being only slightK' 

 greater tiian (sometimes (!(pial to) the least depth of the 

 tail, oi' abuiit ■ ., (\arying between 35 and 43 %) of 

 the length of the longest caudal ravs, which varies be- 

 tween about 17 and 15 "„ (if that of the bodw 



The pectoral tins are set as in the Salmons, rather 

 low. ^\'hen folded, they are of an oblicjuely jiointed 

 shape; when exjiaiidcHl, oval. Their length \aries be- 

 tween 16 and 14 S. of that of the body. Tlie third 

 (second branched) ray is commonly the longest. The 

 ventral tins are of a, broader shape, and are always 

 shorter. Their length ^•arics during growth between 

 14' , and 12 % of that of the body. Their distance 

 from the tip of the snout (i. e. from the .articular knobs 

 of the maxillaries) is generally tlu> same as that of the 

 dorsal fin. The preabdominal length is as a rule more, 

 the jjostabdominal length less, than ' /, of the length of 

 the body, the former varying between about 29 and 

 26 %. the latter between about 22 and 23 ?6 thereof. 



The structure of the scales we have already de- 

 scribed. Below we shall see how the scales of the lateral 

 line indicate the origin of those of Argentina and Sco- 

 lielus, as a transition stage in this respect between the 

 said genera and the Capelin. During the spawning- 

 season both the males and females are covered with a 

 granulate dermal eruption, which varies, however, con- 

 siderably both in prominence and extent. 



The internal organs and the most important ])eeu- 

 liai-ities of the skeleton have also been described in 

 the ])receding jjages. 



The coloration is ])rincipally characterized, here as 

 in the following genus, by the thinness and transpa- 

 rency of the scales; and this transparency is commu- 

 nicated in some degree both to the dorsal musculature 

 and the head, the vertebra;' as well as the cerebral 

 parts being visible in the living fish. The back and 

 the upper portion of the head are pale green or some- 

 times dashed Avith bluish gray, and dow-n the sides, 

 especially in the breeding males, this colour passes into 

 a lustrous violet. Along tin- middle of the sides runs 

 a silvery band, and this silver\' lustre extends to the 

 shoulder-girdle, the opercula, and the cheeks. Under 

 the scales the skin is strewn on the upper parts of the 



11(1 



