14 



ir'-ossible tr drternine. It ir rear.onable , hov/ever, tc infpr 

 that thPTP iray be no fixed rolarity ir the- Irrva of Hydrr- 

 rredusae, for it is v.-ell Irnown that ncrral prbrycs of sr^all 

 sizp vrill dpvel cpe frcr, fra^repts of eggs. 



FLAyULA. 



The blastula Frar'ually elonpatf?, ard beccires narrovrer 

 fer'-irp ? larvr which if urually about three tirer as long 

 as bread ard krowr as a rlarula. 'Fvor, reasurererts tal-en 

 of livinp; rla'-ailae the average rize is about .25 mm. in 

 length a-id .OC tttt, ir the short dia-etrr. These rearure- 

 rer-ts are not constant, the larva beccTi'^ig sojev/hat longer 

 at an older age. The anterior end rerains slightly larger 

 than -he rosterior, but the difference is net as great ar 

 in the blastula. During the bias tula stage the larva sra: 

 near the bottor of the dish; v/hen it attains the rOarula 

 stage it rises a-d svdrs st er near the surface ef the 

 vater for a shorter or Icnger tire. Ihis phenorrenon occurs 

 about tverty-fcur hours after the ergs are fertilized. 



