YOUNG EITTERLING LYING IN THE GILLS OF A FRESH-WATER MUSSEL. 

 In this strange nursery a plentiful supply of fresh water is assured, and they 

 are shielded from enemies. {After Olt.) 



YOUNG PTEROPLATEA SKATE LYING IN THE OVIDUCT. 

 The walls of this grow into the hinder gill-openings and pour into 

 them a milky fluid, which is swallowed. 

 222] 



