No. 447] BREEDING HABITS OF CRAYFISH. 1S5 



were removed and put into dishes of runnin<.,^ water thcv died, 

 except when taken in very late stages with the embryos well 

 formed. The female takes a certain amount of tare of the c-gs 

 which seems to greatly increase their chaiucs oi liatchiii- ; as 

 a rule most of the eggs hatch, but in several rases the e,--s ui>on 

 the abdomen became covered by a fungus which bound them all 

 together into one dead, discolored mass. Still llie temale bore 

 them till long after they should have hatched. l iiat this tun-us 

 attacks the eggs in the open was shown by the tact tliat one 

 of the 39 females taken " in berry " was found to have moulded 

 eggs when received. The female after laying backs into the 

 darkest, most protected corner available and fur a long time keeps 

 the abdomen more or less bent down under the eggs which are 

 then protected from dirt ; but at times the abdomen is straight- 

 ened out and the eggs hanging like bunches of grapes fnjm the 

 pleopods are moved back and forth in a manner well calculated 

 to keep them clean and to insure better aeration, Fig. 7. 



Sometimes also the female may be seen reaching back among 

 the eggs with her smaller claws as if to examine or to clean 

 them. Some of the females died before the young hatched out 

 and this was more often the case amongst the females that had 

 laid in the open and not in the laboratory. If the eggs ueie 

 left upon the dead female they became overgrown b\ ntould and 

 died; but if taken a week before hatching and put mt<» 

 a McDonald fish-jar they hatched successfully m considerable 

 numbers. 



Fertilization. — As most of the eggs hatch and as sections 

 of freshly laid eggs show si^erm nuclei there seems no doubt 



