PLATE 9. 



Sidonops bicolor Lbndenfeld. 

 Figures 1-19. 



1-6. — Cladomcs of plagiofriaencs; magnified 50; phot. Zeiss, apoclir. 16, compens. oo. 4: 



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



2, 6, of a specimen from Station 4531. 



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



7, of a specimen from Station 4551 ; 



S, of a specimen from Station 2781. 

 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 2781 ; 



11, a small one of a specimen from Station 2781. 



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



12, a plagiotriaene with blunt rhabdome of a specimen from Station 2781; 



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 ehoanosome of a specimen from Station 4531; haematoxylin; 

 magnified 2(K); phot. Zeiss, apochr. 8, compens. oc. 6. 



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

 nified 30; phot. Zeiss; planar 20. 



