REPORT OF COMMISSIONERS OF INLAND FISHERIES. 163 



It is here observed that not only are the stage periods of the Euro- 

 pean lobster very long, but the amount of increase in length at each 

 molt is relatively small.* 



The periods are so long, in fact, that Appellof observed that the 

 average number of his lobsters had passed through but five stages 

 (and were in the sixth) when the on-coming cold weather and the 

 consequent lowering of the prevailing temperature of the water put 

 an end to their apparent growth. In December, however, Ehren- 

 baum's lobsters, raised in the warmer waters of Helgoland, were in 

 the seventh stage, and Ehrenbaum concludes that if th-e young 

 lobsters had been hatched earliei; in the summer, they would have 

 passed into the eighth stage before the cold winter months had come,, 

 and put an end to the period of growth (Wachsthumsperiode) . 



Thus Ehrenbaum finally concludes that the European lobster molts 

 7 or 8 times the first summer and autumn of its existence, and attains 

 in this time an average length of 22 to 25 mm. 



Regarding the rate of growth of young lobsters over 8 months old , 

 Appellof observed a few individuals which molted 4 or 5 times during 

 their second year of life. Making use of this, and other data, Ehren- 

 baum estimates in consequence that a young lobster 116 W7n.(4§ inches) 

 in length, is three years old. He formulates the following scheme to 

 demonstrate the rate of development. The "periods" refer to the 

 periods of growth (Wachsthumsperiode) i. e., in this case, years: 



First period 8 to 25 mm Amount of increase, 17 mm. 



Second " 30 to 70 mm " '' 40 mm. 



Third " 70 to 120 mm " " 50 mm. 



Fourth " 120 to 170 mm " " 50 mm. 



Fifth " 170 to 210 mm " " 40 mm. 



Sixth " 210 to 250 mm " " 40 mm. 



From the summation of these facts, we can (having already ob- 

 served the data presented by Herrick, page 159 draw the conclusion, 

 that the rate of growth of the average European lobster may be less 



*These facts will be more evident when a comparison is made with the tables which appear 

 on subsequent pages. 



