EXPLANATION OF PLATES. 



(Plates 37—44 from photographs; plates 45-52 from drawings. In reproduc- 

 tion the photographs have heen reduced to about two-thirds the original size, 

 the drawings have been reduced to about one-half the original size.) 



Plate 37. 



Fig. 1. Sphinctreila bifadalis. Upper surface of sponge showing cloacal de- 

 pression into which oscula open. Two pieces have been cut out on 

 far side of cloaca. On the near side the sponge is attached to a coral- 

 line mass. X%. 



2. SteUetta radicifera. Bisected sponge. XI. 



3. Poccillastra ciliata. Upper and lateral margins represent the free edge 



of the (lamellate) sponge. A piece has been excised. X%. 



4. TetJiyopsis (labia. Bisected sponge. XI. 



5. Geodia sparsa. Sponge from the side. X%. 



6. Myriastra clavosa (Ridley). Two bisected sponges. In the one to 



the right, the cloaca extends in radially ; in the one to the left, it 

 extends in obliquely. XI. 



7. Characella abbreviatu. Upper surface showing cloaca, opening into 



which are seen two oscula. X%. 



8. Erylus cornutus. Bisected sponge. Cloacal surface above; natural 



outer surface to the right ; left half of sponge badly damaged. X %. 



9. Geodia philippinensis. Sponge from the side. X 1 /?- 



507 



