PLATE 10. 



Geodia ovis Lendenfeld. 



Figures 1-30. 



1-4.— Orthotriaencs; magnified 10; phot. Zeiss, planar 50. 



5._ View of a thick radial slice of the sponge; magnified 1.5; phot. Zeiss, anastig. 480 / 412: 



a, spicule-fur; b, cortex; c, choanosome. 

 6-13.— Large amphio.xes; magnified 10; phot. Zeiss, planar 50. 

 14_16.— Sterrasters; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6: 



14, a side-view; 



15, 16, front-views of the umbilical side. 



17, IS.— The umbilical part of the surface of a st«rraster: magnified 1800; u. v. phot. Zeiss, q. monochr. 



1.7, q. oc. 10: 

 17, focused lower; 18, focused higher. 

 19_23._Cladomes of orthotriaenes; magnified 50; phot. Zeiss, apochr. 16, compens. oc. 2. 

 2.1.— Part of the surface of a sterraster opposite the umbiUcus; magnified 1800; u. v. phot. Zeiss, q. 



monochr. 1.7, q. oc. 10. 

 25.— Part of an afferent pore-sieve; magnified 100; phot. Zeiss, apochr. 16, compens. oc. 6. 

 26.— Tip of an abnormal spicule with numerous branch-rays; magnified 100; phot. Zeiss, apochr. 16, 



compens. oc. 6. 

 27.— Tip of a normal, large amphiox; magnified 100; phot. Zeiss, apochr. 16, compens. oc. 6. 

 28.— The cut face of the halved specimen; reduced 1 : 0.76; phot. Zeiss, anastig. 480 / 412. 

 29._ Sterroid ; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6. 

 30._The tip of an orthotriaene-clade with abnormally branched axial thread; magnified 100; phot. 



Zeiss, apochr. 16, compens. oc. 6. 



