PLATE 12. 



Sidonops angulata Lendenfeld. 



Figs. 1-4, 16, 19. 

 Figs. 5-8, 17, 20. 

 Figs. 9, 10. 



Figs. 11-15, 18, 21, 22, 



var. megana Lendenfeld (lobose form), 

 var. megrana Lendenfeld (massive form), 

 var. orthotriaena Lendenfeld. 

 var. microana Lendenfeld. 



1-14. — Cladomes of anaclades; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6: 



I- 4, of the lobose specimen of var. megana ; 

 5-8, of the massive specimen of var. megana; 

 9, 10, of var. orthotriaena; 



II- 14, of var. microana; 



1, 5, of anatriaenes with long equal clades; 



2, 4, 12-14, of anatriaenes with short equal clades; 



3, 6, 8, 9, of anatriaenes with medium-sized equal clades ; 

 7, of an anatriaene with medium-sized unequal clades; 

 10, 11, of anadiaenes with short clades. 



15. — The acladomal end of the anatriaene of var. microana, the cladome of which is represented in Fig. 



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



16, 17. — Groups of spicules from spicule-preparations; magnified 10; phot. Zeiss, planar 50: 



16, of the lobose specimen of var. megana; 



17, of the massive specimen of var. megana; 



a, slender, dermal, simply curved amphioxes; b, slender, dermal, angularly bent amphiox; 

 c, stout, choanosomal amphioxes ; d, plagiotriaenes. 



18-20. — Views of three of the specimens; phot. Zeiss, anastig. 480 / 412: 



18, var. microana; magnified 1.1; 



19, the lobose specimen of var. megana; reduced 1 : 0.86; 



20, the massive specimen of var. megana; reduced 1 : 0.9. 



21, 22. — Groups of plagiotriaenes from a spicule-preparation of var. microana; magnified 10; phot. 

 Zeiss, planar, 50. 



