PLATE 23. 



Geodia mesotriaena Lendenfeld. 



Figs. 1, 2. — var. microana Lendenfeld. 



Figs. 3, 5, 6, 8, 9.— var. pachana Lendenfeld. 

 Figs. 4, 7, 10-25.,— var. megana Lendenfeld. 



l-12.-Cladomesof anatriaenes; magnified 100; phot. Zeiss, apochr. If), compens. oc. 6: 



1, 2, of fully developed anatriaenes of var. microana; 



s', 5, 6, 8, 9, of fully developed anatriaenes of var. pachana ; 



4, 7, of a young anatriaene of var. megaim; 



10-12 of fully developed anatriaenes of var. megarm. 

 13-19.— c'ladomes of teloclades and mesoclades of var. megana: magnified 100; phot. Zeiss, apochr. 



16, compens. oc. 6: , ■ ■, <■ i i .i,„ 



13, of an irregular mesoprotriaene with branches forming a second verticd of elades on the 



epirhabd ; 



14, of a mesoprotriaene with one clade abruptly bent, and one strong>Me; 



15, of an irregular protriaene with one clade nearly vertical ; 



16, of a regular orthotriaene; 



17, of an irregular mesanatriaene with strongly deflected epirhabd; 



18, of a young regular mesoprotriaene ; 



19, of a regular mesoprotriaene fully developed. 



20-23.- Cladomes of orthotriaenes of var. megami; magnified .50; phot. Zeiss, apochr. 16, compens. 

 oc. 4: 



20, of an orthotriaene fully developed with elades not verj' different in size; 



21, of a young quite regular orthotriaeTie ; 



•'2 of an orthotriaene fully developed with one clade much shorter than the others; 

 23! of an orthotriaene fully developed with one clade abruptly bent and shorter than the others. 

 24, 25.— Radial section through a part of the cortex and the adjacent choanosome of var. megana: 



24, magnified 10; phot. Zeiss, planar 50; 



25, (a part of 24) magnified 30; phot., Zeiss, planar 20; 



a outer surface; b, sterraster-armour; c, superficial canals; d, chone; e, radial mam choano- 

 somal canal; f, tissue free from flagellate chambers surrounding the radial mam choano- 

 somal canal; g, tissue containing flagellate chambers; h, radial spicule bundles; 1, small, 

 more or less radial, dermal rhabds protruding beyond the surface; k, chonal canal. 



