22 



That this idea is correct, tliat it is not only possible aud probable but in 

 fiill agreemeiit witb the actual conditions, will be proved here. And the proof 

 consists in following tbe development and growtli oi the scales tbroughout a period 

 of growth. If we examine eels which nieasure 18 cm. or more in length iu tlie 

 autumn, we iind scales in their skin. In specimens of 18 — 20 cm. in length, 

 there are often very few scales; somefimes they form only a row above and along 

 the lateral line on the central part of the tish, it happens even that not so many 

 are formed as to form a continuous row. The scales do not show concentric zones 

 or rings; there is only a small, oval, plate-like body which however has quite the 

 structure described above (the surface is divided into small medallions etc.) We 

 may call this the central zone or only the centre. — It is characteristic of the 

 scales at this period of the year, that the outermost row of the medallions is also 

 quite surrounded by the margin of the underlying plate, so that this is seen as a 

 coutour or frame, everywhere very distinct, outside all the small piates; it is the 

 more apparent as it is marked by a much darker colour than these. — The small 

 piates or medallions have distinct and sharp contours, and decrease in size out 

 towards the margin of the scale. The whole has a firm, solid aud finished 

 appearance. — In May we again take up the investigation aud on eels of the size 

 mentioned above we find scales with quite the same appearance. The growth of 

 the scale has thus not yet begun, which indeed was to be expected, as the eel 

 itself has not yet begun to grow; see Tab. 1 — 2. — This is the condition in May 

 and partly in June ; yet at the end of this month I have observed some scales 

 which had uudoubtedly begun to form a concentric zone outside the central zone; 

 and from the middle of July the newly formed zone takes on a considerable 

 breadth and is now found on practically all the scales iuvestigated. — In longer 

 eels whose scales in spring show oue to several zones outside the central zone, 

 the condition is quite the same. It is thus noted in the Journal for July 17th, 

 that the annual rings on many of the scales from the summer of 1906 seem 

 ahnost completed. The annual rings seem thus to grow very quickly. — Table 3 



Table 3. 



