957 



to the preoperculum. Its externalljf visible part (licliiw 

 the iircoperculmn) is, however, sword-slmpcil ;niil of 

 unit'oriii l)rc;i(ltli. 'riie hind iuari;iiis ot'iho pi'copci'ciihnu 

 and iiitcTo|i(_Tculiini to^u'ether tunii ii slii^htly curNi'd iiin', 

 COiitiniK'il liclow tlio lattci' in ;i contour I'orniiiii;' an 

 obtuse anji'le witli the inferior ninrgin of tiie suboper- 

 cuhiin. In tlie Herring, as in the other Clupeoids, 

 ■\ve find a l)onc tliat seems at first siglit to 1)e a lower 

 Sid)o|)ercuhiui, forming an angular break at the lower 

 iiostii'ior angle of the opercular apparatus. In order 

 that till' apjiaratus may be more firmly closed at this 

 angle, the anterior margin of the shoulder-girdle rises 

 at this point in the form of an elongated, sharp-edged 

 knob, the substratum of which consists of an ujn-ight 

 process (clj), fig. 238, p. 950) from the ui)]ier margin 

 of the horizontal arm of the clavicle. ( )n closer exa- 

 luination, however, it soon appears that the a|)parent 

 lower subopercnlum is really the hindmost of the three 

 broud branchiostegal rays set on the epihyoid bone. 

 The first five rays, which are situated on the cerato- 

 hyoid bone, are subulate and more curved. The branchio- 

 stegal membranes are free both from each other and the 

 isthmus, and overla]) each other onlv to a verv small 

 extent in the extreme front, the left membrane lying 

 outside the right. 



The dorsal hn, wliich is trapezoidal in shape, begins 

 at a distance from the tip of the snout (the articular 

 heads of the maxillaries) measuring 47. — 51 % of the 

 length of the body. The length of its base is 13 — 10 %, 

 and its greatest height (the length of the first or second 

 branched ray) 12 — 10 % (less frequently 9 %), of the 

 length of the bodv. The anal fin is of a similar shape 

 as the dorsal Init much lower. The distance between 

 its beginning and the tip of the snout is 71 — 75 %, the 

 length of its base 11 — 10 96 (exceptionally 12 or 9 ?»), 

 and its greatest height o'/j — 4"2 % (exceptionally 6 or 

 4 %), of the length of the body. The caudal tin is 

 deeply forked, the lower lobe being somewhat longer 

 and more pointed than tlie u])per. Its middle ravs 

 occujjv about 5 — 4 % of the length of the body, and 

 measure only ^'3 — ' _, of the length of the longest rays 

 in the tin. 



The pectoral fins are set low, as in the Salmons, 

 and of an oval, obliquelv pointed shape, the second 

 branched (third) raj' being usually the longest. Their 

 length varies between 16" and 13 % of that of the body, 



" In young Herrings sometimes 17. 

 ' In the fry sometimes 50' ,. 



and during youth is generally somewhat more, in old 

 specimens perceptibly less, than half the preabdominal 

 length, wliich incrc^ases even relatively with age, from 

 30 to 35 or neai'ly 36 ?o of the length of the body. 

 The ventral lins are broader and shorter, but triangular. 

 Their length varies between 10 and 8 % of that of the 

 bod}'. Their insertion always lies some distance, though 

 in joung specimens tliis is sometimes very small, behind 

 the iicr]iendictdar from tlie beginning of the dorsal fin, 

 and at a distance iVoni the tip of the mouth measuring 

 51'' — 55 % of the length of the body. The postabdo- 

 minal length is about "/s "f the preabdominal, and 

 varies between about 20 and 23 ,» (exceptionally 24 %) 

 of the length of the body. 



The thin and deciduous scales (fig. 239) are round 

 or quadrilateral with rounded angles. The hind (free) 

 part is indented at tlie margin with small, rounded 

 sinuses, and shows onh- faint traces of radiating grooves. 

 The anterior jiart (covered and about twice as large) is 



Fig. 239. Scale from tlie left side of a Clupeu harenijns 

 3 dm. long. X 3. 



smooth-margined and marked with extremely fine and 

 numerous, irregidarl}' undulating and confluent, trans- 

 verse stria?, without radiating grooves or with only ru- 

 diments thereof, in the form of a few streaks (5 — 7 

 upwards and downwards) obliquely crossing the others. 

 In this striature the growth-rings of the scale also 

 appear as concentric lines. The lateral line does not 

 pierce any scales — onlv in exceptional instances are 

 there a fe\v perforated scales in front — but under the 

 scales it runs straight from the upper clavicle to the 

 middle of the base of the caudal fin. The singular 

 marginal scales of the bell)' (fig. 240) are of an oblique 

 diamond-shape, with a strengthening ridge in the me- 

 dian line of the belly, ending in the backward spine, 

 and another on each side, continued by the upward 

 process. They are remarkable in the Herring for their 

 number, Avhich is greater than in the following species, 

 being as a rule, according to Heixcke, 27^ — 30 (excep- 



