PLATE 8. 



Sidonops oxyastra Lendenfeld. 



Figures 1-15. 



1-3. — Stcrrastors; magnified 30O: 



1, phot. Zci.ss, apochr. 4, compens. oc. 6; 



2, 3 phot. Zeiss, horn. iram. apochr. 2. 



4. — Group of spicules from a spicule-preparation ; magnified 30; phot. Zeiss, planar 20: 



a, large amphioxes; b, lateral xnews of plagiotriaenes; c, apical view of a plagiotriaene-cladome. 

 5. — Group of large amphioxes from a spicule-preparation; magnified 30; phot. Zeiss, planar 20. 

 US. — Part of Ihe lateral surface of a thick-rayed sterraster; magnified 1800; u. v. phot. Zeiss, q. 

 monochr. 1.7, q. oc. 10: 

 6. focased high ; 7, focused lower: 8, focused still lower. 

 9. — Part of the lateral surface of a sterraster not quite fully developed; magnified 1800; u. v. phot. 



Zeiss, q. monochr. 1.7, q. oc. 10. 

 10, 11. — Part of the lateral .surface of a thin-rayed sterraster; magnified 1800; u. v. phot. Zei.ss, q. 

 monochr. 1.7, q. oc. 10: 

 10, focused higher; 11, focused lower. 

 12. — Sterraster; magnified 1000; phot. Zeiss, horn. imm. apochr. 2, compens. oc. G; the centrum of the 

 spicule in focus: 



a, rosette of central granules; b, umliilicus. 

 13, 14. — Views of parts of the surface (superficial paratangential sections) with transmitted light; 

 magnified 20; phot. Zeiss, planar 20: 



13, of a region Waring afferent pores; 



14, of a region bearing efferent pores. 



15. — Part of a region of the surface with afferent pores; magnified 100; phot. Zeiss, apochr. 16, compens. 

 oc. 6. 



