PLATE 27. 



Geodia agassizii Lendenfeld (adult). 

 Figure.s 1-19. 



1. — Radial section through the region bearing efferent pores of a large specimen from Station 4193; 



magnified 7.5; phot. Zeiss, planar .50: 



b, sterraster-armour of the cortex; d, large afferent canals; e, large efferent canal. 



2. — Radial section through the region bearing afferent pores of a medium-sized specimen from Station 



3168; magnified 7.5; phot. Zeiss, planar 50: 



a, ectochrotal outer layer of the cortex, free from sterrasters, with small, radial dermal 

 amphioxes; b, sterraster-armour of the cortex; c, subcortical cavities; d, large afferent 

 canal. 



3-13. — Groups of spicules from centrifugal spicule-preparations; magnified 300; phot. Zeiss, apochr. 

 4, compens. oc. 6: 

 3, 4, 9, of specimens from Station 2978; 



5, of a specimen from Station 2887; 



6, 11, of a specimen from Station 3168; 



7, of a specimen from Station 4551; 



8, of a specimen from Station 4193; 

 10, of a specimen from Station 2886; 



12, of a specimen from Station 4199; 



13, of a specimen from Station 3088; 



a, small dermal amphioxes: b, large choano.somal oxyasters; c, large cortical oxysphaerasters ; 



d, small strongylosphaerasters. 

 14. — Group of asters from a centrifugal spicule-preparation of a specimen from Station 4193; magnified 

 500; phot. Zeiss, hom. imm. apochr. 2, compens. oc. 6: 



b, large oxyaster; c, large oxysphaeraster ; d, small strongylosphaeraster. 



15-19. — Gi'oups of sterrasters from spicule-preparations; magnified 200; phot. Zeiss, apochr. 8, com- 

 pens. oc. 6: 



15, of a specimen from Station 2978; 



16, of a specimen from Station 4551; 



17, of a specimen from Station 4193; 



18, of a specimen from Station 3088; 



19, of a specimen from Station 4199. 



