24 



in size out towards the margin of the scale (or zone) and have sharply defined 

 contonrs. — If ou the other hånd the scale is growing the outer border is quite 

 wanting; the small piates extend out to the margin of the scale which has thus 

 an irregular form, the more so as their contour is often of quite a different a]ipear- 

 ance from that of the completed scale. They are rarely sharply defined, as a 

 rule more or less projecting, and the oue margin — the outer — is quite wanting, 

 so that in appearance they are u-shaped, and thus agree with what Baudelot says 

 of the calcareous piates found along the outer margin of the zone; »they often 

 show quite a rudimentary appeai'ance; they are sometimes reduced to a comb 

 pure and simple.« This just suits the appearance of the still incomplete calcar- 

 eous piates; and it is rgasouable to suppose that among the scales Baudelot exa- 

 miued were some still growing, without his being aware however that this was 

 the reason for their peculiar appearance. — At the same time the whole of the 

 scale has a le.ss transparent, yellowish shimmer over it and a looser structure; this 

 may arise from the cireumstance that the ground-substance itself, into which the 

 small piates are fixed by their lower end-surfaces, has not yet attained the firm- 

 uess and tliickness, which the whole period of growth gives. — ■ Lastly, the small 

 piates do not decrease in size towards the margin, so long as only a single or a 

 few rows are laid down. 



We come finally to the questious — wheu are the scales first laid down 

 and where are they tirst found. The latter may be answered by saying, that the 

 scales first appear along the upper margin of the lateral line, some distance in 

 front of a line drawn from this perpendicularly through the anus; they are laid 

 down on both sides of this line, towards the head and towards the tail and like- 

 wise up on the sides of the fish. The scales along the lower border of the lateral 

 line may be laid down at about the same time as those above or somewhat 

 later, and here also the development of the scales in the skin progresses in the 

 same manner as above the lateral line. Sometimes so few are formed in the 

 summer in which the first scales are laid down, that a continuous jow even does 

 not occur along the lateral line, but only a few isolated scales are seen here and 

 there. The rule is, however, that several to many rows are formed. — In deter- 

 mining the age, care must naturally be taken to obtain the oldest scales, and one 

 should therefore select the scales at the lateral line somewhat in front of the anus. 



»At about this length, ca. 200 mm., the eel begius to have scales« was 

 written by C. G. Joh. Petersen in the Report previously cited (V. 1894). This is 

 certainly somewhat too high; as a general rule we might say: there are completely 

 formed scales in eels of 18 cm. or over. This does not exclude the possibility of finding 

 scalelesseelsof 18, 19and very rarely of20cm.; and ou the other hånd, wemay fiud scales 

 in smaller eels, of 17 and extremely rarely 16 cm. — but this as a rule is in sum- 

 mer; the scales are then growing and before growth is coucluded the eel will 

 have reached the size of 18 cm. — This size thus represents a limit, sealelimit, 

 which divides the eels into 2 great portions: the naked and the scaled. When 

 the eels during their growth pass this limit — or perhaps even a little before — 

 they begin to have scales. — At what period during growth does this occur? 

 Though I have searched a great deal I have not been able to find scales »in 



