LIFE HISTOUY OF LAKE^HERRING OF LAKE HURON 277 



fish will observe certain rings thereon. And as many rings as there may be, so many 

 yeai-s will be the age of the fish." 



Kuntzmann (1S29) maintained that no relation existed between concentric lines 

 on scales and age, as the scales of old carp possess no more of these ridges than those 

 of 3-oung carp. Similarly, Blanchard (1866) stated that the concentric striae are as 

 numerous in verj^ small as in very large fish of the same species. Agassiz (1834), 

 however, believed that the concentric lines are the reflexed edges of the lamell<E and 

 increase in number with the growth of the scale. Mandl (1839) claimed that the 

 formation of these lines is linlced closely with the peripheral growth of the superior 

 layer of the scale, while Williamson (1851) asserted that these ridges are not lines of 

 growth "but the result of a peculiar arrangement of the superficial tissue of the 

 scale." 



Vogt (1842) discovered that scales do not appear in salmon until the third month 

 after hatching, and that the concentric lines are relatively few in number in very 

 young fish but very numerous in adult fish. 



Steenstrup (1861) is apparently the first to state specifically that the scales of 

 osseous fishes persist during the entire life of the fish and grow with the growth of the 

 animal. 



Baudelot (1873) made a comparative study of scales, employing a dozen species 

 of fish. He noted, among other things, the variation in the number and character 

 of the concentric ridges with the species and with the individuals of a species. He 

 observed that these Unes remained fairly constant in number with scales taken from 

 the same region of the body of a fish, but that they increased in number in the older 

 individuals of a species, the number of ridges increasing proportionally with the age 

 of the fish and the size of the scales. He discovered, further, that the concentric 

 ridges varied in their degree of separation and regularity, so that concentric zones 

 were visible on the scale surface. He believed that the cause of this phenomenon 

 was veiy unstable, but lacking sufficient data left the matter undetermined. 



It was left for Hintze (1888) to link Baudelot's "zones" with Leeuwenhoek's 

 first theory of age determination. Hintze was enabled to correlate the two by his 

 knowledge of the age and life history of the carp, upon which he worked. Carp of 

 commercial ponds Vv'ere employed. Due to the presence of accessory annuli, however, 

 Hintze made an error of one year in his interpretations, which error caused the tem- 

 porary abandonment of his theory. His work is considered more in detail in a later 

 section (p. 294). 



Hintze's theory had at least one adherent, Victor Burda, for Max von dem Born 

 writes (1894, p. 58) _. "Nach Burda kann man das Alter der Karpfen an den 

 Jahrcsringen erkennen, welche auf den Schuppen sichtbar sind, wenn man diese in 

 Spiritus legt, und von Schlamme befreit; ich habe mich von der Richtigkeit dieser 

 Mitteilung durch den Augenschein iiberzeugt." 



Fritsch (1893, p. 89) enumerated the circuli (Anwuchsringe) in the scales of 

 salmon of known ages and of various lengths (34 millimeters to 90 centimeters) and 

 concluded: "Genaue Verfolgung dieser Zunahme der Anwachsringe der Schuppe 

 mit zuiiehmcndera Alter diirfte einen Anhaltspuidct geben nach der Zahl der Anwachs- 

 ringe bei grossen Lachsen das Alter zu bestimmcn. Bei Salmlingen, von denen ich 

 voraussetzte, dass sie schnell wachsen, fand ich die Anwachsringe weiter von ein- 



