EXPI.ANA'I'ION OF PLATE XII. 



Fig. 17. Euxyongia irregularis, var. silicata, Lendonfeld. 

 „ 17a. 

 ., 18. Eiispanijia, irregularis, vwv. arcoiata, Wbitelegge. 



19. Kuspongia illawarra, Whitelegge. 



20. Euspongia officiiialis, var. dura, Lendenfeld. 



21. Eu^pongia ■pikci, Hyatt (No. 351). 

 21a. Euspongia piJcei, Hyatt. 



22. Hippospongia equina, var. elasiica, Lendenfeld. 



All the 



figures are reduced to about one-fourth the natural size. 



