Plate 25. 



Microphotographs of thick unstained preparations showing skeletal arrangement. 

 Fig. 1. PhakeUia lamelligera. Section vertical to surface, and passing completely 



throngh lamellate wall; in horizontal plane of sponge; 

 X 15. 



" 2. Auletta dendroiihora. From a median longitudinal section through a " person." 



Left margin of figure represents surface of sponge ; 

 right margin, surface of paragastric cavity. Along 

 latter margin appears a longitudinal skeletal fibre, 

 from which short echinating spicules project ; x 30. 



" 3. PhakeUia lamelligera. Skeletal lamella, seen from its flattened face. Long 



projecting spicules along right and left x^iargins of 

 figure are the spicules projecting from snrfaces of 

 sponge. Lamella was dissected out and cleaned with 

 potash : X 10. 



" 4. " " Idem. Figure was not well reproduced, and the pro- 



jecting (prostal) spicules are indistinct ; x 10. 



