PLATE 9. 



Sidonops bicolor Lendenfeld. 

 Figures 1-19. 



1-6. — Cladomcs of plagiotriaenes; magnified 50; phot. Zeiss, apochr. 16, compens. oc. 4: 



1, 3-5, of a specimen from Station 2958; 



2, 6, of a specimen from Station 4531. 



7, S. — Long slender amphioxes; magnified 20; phot. Zeiss, planar 20: 



7, of a specimen from Station 4551; 



8, of a specimen from Station 2^81. 



9-11. — Stout amphioxes; magnified 20; phot. Zeiss, planar 20: 



9, a large one of a specimen from Station 4531 ; 



10, a medium-sized one of a specimen from Station 2^81; 



11, a small one of a specimen from Station 2|'81. 



12-14. — Plagiotriaenes; magnified 20; phot. Zeiss, planar 20: 



12, a plagiotriaene with blunt rhabdome of a specimen from Station 2t81; 



13, a plagiotriaene with pointed rhabdome of a specimen from Station 2958 ; 



14, a plagiotriaene with pointed rhabdome of a specimen from Station 2781. 



15, 16. — Parts of radial sections through the cortex and adjacent parts, showing the chones of a speci- 

 men from Station 4420; magnified 30; phot. Zeiss planar 20: 

 a, surface of the sponge. 



17. — Part of a radial section through a specimen from Station 3168; magnified 7.5; phot. Zeiss, planar 



50: 



a, surface of the sponge. 



18. — Part of a section through the choanosome of a specimen from Station 4531; haematoxylin; 



magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6. 



19. — Part of a section through the choanosome of a specimen from Station 3168; haematoxylin; mag- 



nified 30; phot. Zeiss; planar 20. 



