160 MAKKKTA1U.K BRITISH MARIXK FISHES 



were captured which were if^ inches long, and on June 23rd 

 others i ^ inches. The specimens taken at the end of May and 

 June loth must have been hatched about the middle of April, 

 and so would be about six weeks old. 



It was found that the transformation from the scaleless, trans- 

 parent, larval condition, to the condition of perfectly formed 

 small herring took place in the Schlei in July, and by the end 

 of that month the majority had got beyond the intermediate or 

 transition period and were fully developed. They were then i| 

 to 2\ inches long. The process of change, and the time required 

 for it, were observed not only by the capture of specimens from 

 time to time, but also in specimens confined in a floating box. 

 These specimens were I inch or a little more on June nth when 

 the experiment commenced, and on August ist, or after about 

 six weeks, were ii inches long, and were silvery and covered with 

 scales. 



At the end of August and beginning of September the little 

 herrings left the mouth of the river and were found in the 

 neighbouring bays, but mixed with other larger herrings evi- 

 dently derived from a different and earlier spawning. Meyer 

 therefore measured the growth by taking the lengths of the 

 smallest fish in each catch ; the results were these : 



Inches. 



1876. 1 4th November ........................ 3^3 



End of November ..................... 3-5 



End of December ..................... 3-9 



1877. End of January ........................ 4-3 



End of February ........................ 4-5 



End of March .......................... 4-9 



End of April ......................... 5-4 



As the smallest fish only were measured, we may conclude 

 from this that these herrings were 5 to 6 inches long when one 

 year old. 



In 1878 the same naturalist took a great deal of trouble in 

 order to try to rear in confinement herring larvae hatched from 

 artificially fertilised eggs. The larvae were placed in a large tub 

 about three feet wide and two feet deep, with a wooden cover. A 

 hole was made in the side about midway between top and 

 bottom and plugged with a sponge. Through this the water 

 gradually drained away until it was level with the hole. Clean 

 water from the Bay of Kiel was poured in once a day. After 



