ei^-tocyUs- .Vlv.;{vA jMocjfea conj-edaie ^ \ ) ^ J ^ I 



^ v.: V .' J to jorm ^emmulcs ®^5^ VenUt^ea jgemmufe* 







Fig. 86. — Spongilla, a fresh water sponge. Diagrams show the congregation 

 of special cells (statocytes) to form gemmules from which a new colony of 

 Spongilla may arise. (Copyright by General Biological Supply House, Inc., 

 Chicago. ) 





Fig. 87. — Types of sponges shown in section with the pores and canals repre- 

 sented somewhat diagrammatically. Arrows show the direction of water flow 

 A, Asconoid type, such as Leucosolenia; E, syconoid type, such as Scypha 

 (Grantia) ; C, leuconoid (Rhagon) type, as in commercial sponges. 



7, Incurrent pore (ostium). 



2, Incurrent canal. 



.?, Connecting structure (prosopyle). 



4, Excurrent (radial) canal. 



5, Flagellated cell (choanocyte). 



6, Apopyle (excurrent pore). 



7, Gastrocoel or spongocoel (central cloacal 

 cavity). 



8, Osculum. 



9, Dermal epithelium. 

 \0, Mesenchyme. 



II, Gastral epithelium. 



72, Subdermal cavity. 



13, Dermal pore or ostium. 



