Plate 24. 



Microphotographs of thick unstaiued preparations showing skeletal arrangement. 

 Fig. 1. lophon chelifer ostia-magna. From a section vertical to surface and radial to 



margin of sponge, and passing through a large 

 marginal osculum and efferent canal (c/. Fig. 4, 

 PI. 20). Figure includes thickness of sponge 

 lying between surface and canal. Eight margin 

 of figure represents surface of sponge ; left 

 margin, canal wall; x 15. 

 " 2. lophon lamella. Surface; reticulate condition ; x 15. 



" 3. " " Section vertical to surface, and through entire thickness of 



lamellate body. Right and left margins of figure repre- 

 sent surfaces of body ; x 15. 

 4. " " Idem ; x 15. 



