Plate 20. 



Fig. 1. loplion indentatus. From a photograph ; x \. 

 " 2. lojjhon chdifci- ostia-maffna. Microscleres ; a, bipocillus from concave side ami 



smaller end ; l>, anisochela in lateral view ; 



c, bipocillus in slightly oblique lateral view ; 



d, bipocillus from concave side, larger plate 

 in optical section ; x 1000. 



" 3. lophon lamella. From a photograph. Oscula depressed and surrounded with 



coUenchyma ; x \. 

 " 4. lophon chelifer ostla-vingna. From a photograph. Margin of sponge, with large 



oscula, to the right ; x \. 

 " 5. lophon indentatus. Skeletal style ; x 250. 

 " 6. " " Tylote ; x 250. 



" 7. lophon lamella. Microscleres ; n, bipocillus from convex side ; h, anisochela iu 



lateral view ; e, bipocillus in lateral view ; x 1000. 

 " 8. " " Skeletal style ; x 250. 



" 9. " " Tylote; x 250. 



" 10. lopihon chelifer ostia-magna. Skeletal style ; x 250. 

 " 11. " " " Tylote ; x 250. 



" 12. lophon lamella. From a photograph ; upper surface ; x |. 

 " 13. " " From a photograph. Lower surface of the specimen shown in 



Fig. 12 ; X \. 

 " 14. lophon lamella indivisus. From a photograph ; under surface; x {. 

 " 15. " " " Microscleres; a, bipocillus from convex side; /*, 



anisochela in ventral view ; e, bipocillus from 

 concave side; d, bipocillus in lateral view; e, 

 bipocillus, apical view of larger end ; /, bipo- 

 cillus, api(!al view of smaller end; x 1000. 

 " 16. " " From a photograph. Upper surface of specimen 



shown in Fig. 14; x }. 



