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THE AMERICAN NATURALIST [Vol. XL 



swiuifj: about through 120° till the right chela came against the 

 end of the dish and the animal turned over onto the left side and 

 rested with the anterior part elevated and the abdomen u])on the 

 bottom. Lying thus for some minutes the crayfish made no 

 mo\om(Mits of any external organs. The tail-fan had receded a 

 little l)ut was still as far forward as tlie bases of the second thoracic 

 legs. 



Two niinutcs later, /. r.. ai)()iit half an hour from the beginning 

 of the "nlairiiig" pioccss. ihc continued recession of the al)domen 

 laid l)arc the bases of the third legs and over the edge of the telson 

 an egg \\'as seen in the glaire above tlie telson. Thus the glair- 

 ing period had already passed and the extrusion of eggs had been 

 going on. A minute later the withdrawal of the abdomen stretched 

 the glaire like a membrane from the edge of the telson to the region 

 of the anterior thoracic legs and through this veil rows of eggs 

 were seen issuing out from the opening of the oviduct on the base 

 of the third right thoracic leg. The extrusion of eggs, however, 

 will be described below from other more normal cases in which 

 the crayfish lay upon its back and not upon one side when the 

 eggs were extruded. 



The actual extrusion of eggs was seen in six crayfish and took 

 place in approximately the following nninber of minutes in tiiese 

 cases: 10, 10, 13, 17, 20, ;;(). Thi. is in strong contrast to the 

 statement of Chantran that, in Astacus, the extrusion of eggs 

 lasted from one to several hours. Possibly lie confounded the 

 period of extrusion with the following period of "turning" which 

 mav well exist in Astacus and which in Cambarus occupies several 

 hours. 



In Cambarus as in Astacus it was very unusual for eggs to be 

 laid in the day time and the above six cases were seen in the day 

 time only from the employment of the follow^ing expedient. Cray- 

 fish that had finished the cleansing process were prevented from 

 laying by being kept all night in running water barely sufficient 

 to moisten them and then put into deeper water in the day time. 

 After two or three repetitions of this treatment some ten females 

 laid in the day time, several hours after being put into deep 



Though no crayfish laid when merely moist, one small specimen 



