SPONGES. 243 



PLATE V. 



Fig. 1. Stifbti ej'tema; R.N. 167. Spicules. 



a.-d., (lichotriames (.s7/. = shaft), x 230 ; <., ?., microxe.a, x 530. 

 2. Copputiax replant ; R.N. 242. Spicules. 

 a.-r., oxea, x 52 ; */., chiasters, x 530. 

 3. Asteropus haeekeli ; R.N. 219. Spicules. 



a., oxeote, x 52 ; b., oxyaster, x 530 ; <:, </., sam'dasters, x 530. 

 4. Cri//iti>t/'tlii/u agglutinans ; R.N. 62. Half the specimen, after division in the median plane. 



Natural size. 



rh., choanosomc ; ect., ectosome ; f.b., foreign bodies adhering to the surface ; /./., inner fibrous 

 layer of ectosome ; f.p., finger-shaped process of ectosome ; r., process of ectosome 

 flattened at the end and containing longitudinal canals. 

 ,, 5. Cryptotcthya aggliitinana ; R.N. 62. Spicules. 



a., b., oxea, x 52 ; c., chiasters from ectosome, x 230. 

 6. Hi/medesmia atrmslellifera ; R.N. 320. Spicules. 



a., tylostyle, x 230 ; b., c., </., asters, x 530. 

 7. Spirastrella tentonddcs ; R.N. 239. Spicules. 



a., b., tylostyli, x 230 ; t.-g., spirasters, x 530. 

 8. Negmnbo trnuistrllala ; R.N. 362. Spicules. 

 u.-c., styli, x230; d., sanidasters, x 530. 

 9. Cliona margaritifrrai ; R.N. 261. Spicules. 



a., tylostyle, x230; b.-d., spirasters, x530; >'., </., intermediate microscleres, x530; /(., /.-., 



spined microxea, x 530. 

 10. Hiibrrifrx n -unaMiA ; R.N. 315. Spicules. 



., //., tylostyles, x 230 ; f.-f/., heads of tylostyles, showing variations, x 530. 



PLATE VI. 

 Xrnospmyia patellifonnis, R.N. 375. 



Fig. 1 . Entire specimen (young), upper surface, slightly diagrammatic, x 2. 



., projection caused by foreign body; m.f., marginal fringe of spicules; m.p.g., marginal pore- 

 grooves ; o., vents ; r.p.y., radiating pore-grooves, feebly developed. 

 ,, 2. Radial vertical section, showing the ectosome (cortex), the sand-free portion of the choanosome, 



and part only of the sandy layer of the choanosome ; slightly diagrammatic. 

 cart., cortex ; d.b., dermal brushes of styli ; ex.c., exhalant canal ; f.b., bands of fibrous tissue 

 running inwards from the cortex to the sandy layer; m.f., marginal fringe of styli; 

 ni.ji.f/., marginal pore-grooves, showing inhalant pores and canals; o., vent.; s.g., sand 

 grains. 

 ., 3. Small portion of similar section, including the entire thickness of the cortex and a small portion 



of the choanosome, x 230. 

 rori., cortex; f.b., band of fibrous tissue running inwards from the cortex ;" fl.t., flagellate 



chambers ; xcl., scleroblasts, containing small asters. 

 4. Megascleres. 



a., b., styli, x 52 ; b'., b"., basal and apical portions of />, x 230. 

 5. Larger microscleres, x 230. 



a.-c., various forms of aster; </., a much-branched aster frdm the interior of the sponge. 

 6. Smaller microscleres, x 530. 



a.-//)., various forms of aster. 



2 I 2 



