GRANTIA. 21 



// the time allows, draw ova, sperm-spheres, segmenting eggs, 

 and embryos. 



It is desirable to examine specimens of Leucosolenia, a still 

 simpler sponge, and of some of the more complicated forms, 

 like commercial sponges, Spongilla, Cliona, and Chalina. Why 

 is more than a single osculum desirable in such forms? Under- 

 stand the relation of the internal structure of the complicated 

 forms to the more simple forms. What reason is there for the 

 complication? 



