4 UNIVERSITY OF MISSOURI STUDIES [^Q^ 



regeneration. He says that the antennae are regenerated be- 

 tween two successive moults but that other appendages must 

 pass through three moults in order to be regenerated. In a 

 later paper ('73) he gives an account of his experiments upon 

 the eyes of crayfish. He finds that when a part of the eye is 

 removed regeneration takes place more or less rapidly according 

 to the age of the individual and the season of the year. When 

 the eyes are cut off in October at the close of the moulting sea- 

 son no new growth is apparent until the following May. When 

 the whole eye is excised no regeneration takes place. 



Goodsir ('80) gives a short account of the regeneration of 

 lost parts in Crustacea, and attempts an explanation of the pro- 

 cess, which, however, is not in accordance with results obtained 

 by other observers. 



Brooks ('87) confined his observations to the common lob- 

 ster {Homarus vulgaris). His paper is not at hand and I have 

 but a very meagre account of it. Herrick ('95, p. 105) men- 

 tions some of Brooks' results. They agree with similar observa- 

 tions made by Herrick himself upon the regenerative processes 

 in the lobster. 



Herrick ('95, pp. 104-108) gives a very concise account of 

 his observations upon the regeneration of the chelipeds, anten- 

 nae and some of the periopods of the lobster. He, too, has 

 noticed that the rate at which regeneration takes place varies 

 greatly with the season of the year, the age of the individual, and 

 whether or not the loss of a limb occurs a short time before or a 

 short time after a moult. In the larvae of lobsters the process of 

 regeneration is very rapid. One case is mentioned in which the 

 eheliped was entirely regenerated within fifteen days. Two 

 moults had occurred, however, during this time. In another 

 case there was complete regeneration after a single moult. But, 

 on the other hand, it may require as long as a month for a young 

 lobster to completely regenerate a lost appendage. 



