SPONGES. 243 



PLATE V. 

 Pig. |. Stvba extensa ; R.N. 167. Spicules. 



a.-d., dichotrisenes (sk. = shaft), x230; e., e., microxea, x 530. 



2. CoppaUas repta/ns ; R.N. 242. Spicules. 



.-<., oxea, x 52 ; '/., chiasters, x 5.30. 



3. Asteropus haeehti ; K.N. 219. Spicules. 



., oxeote, x 52 ; 6., oxyaster, x 530 ; c, d., sanidasters, x 530. 



4. Oryplotefhya agglutinans ; R.N. G2. Half the specimen, after division in the median plane. 



Natural size. 

 ch., choanosome; ect., ectosome; f.h., foreign bodies adhering to the surface; /./., inner fibrous 

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

 flattened at the end and containing longitudinal canals. 

 5. Oryptotethya aggluimans ; R.N. 62. Spicules. 



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

 G. Hymedesmia curvistellifem ; R.N. 320. Spicules. 

 a., tylostyle, x 230; b., r., d., asters, x 530. 

 ,, 7. Spirastrella temtorioides ; R.N. 239. Spicules. 



a., b., tylostyli, x 230 ; c.-g., spirasters, x 5.30. 

 8. Negombo tenuistellata ; R.N. 362. Spicules. 

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

 9. Cliona margaritiferm ; RN. 261. Spicules. 



n., tylostyle, x230; b.-ih, spirasters, x530; <:, ;/., intermediate microscleres, x530; /(., /., 

 spined microxea, x 530. 

 ,, 10. Suberites cruciatus ; R.N. 315. Spicules. 



it., ]>., tylostyles, x 230; c.-g., heads of tylostyles, showing variations, x 530. 



t 



PLATE VI. 

 Xeiwaporujia pateUiforum, R.N. 375. 



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



., projection caused by foreign body; in./., marginal fringe of spicules; mjp.g., marginal pore- 

 grooves; c, vents; r.p.g., 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; il.b., dermal brushes of styli; ex.c, exhalant canal; f.b., bands of fibrous tissue 

 running inwards from the cortex to the sandy layer; //(./., marginal fringe of styli; 

 m.p.g., 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. 

 fur/., cortex; /'./'., band of fibrous tissue running inwards from the cortex; Ji.c, flagellate 

 chambers ; scl., scleroblasts, containing small asters. 

 4. Megascleres. 



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

 5. Larger microscleres, x 230. 



a.- 1-., various forms of aster; </., a much-branched aster from the interior of the sponge. 

 6. Smaller microscleres, x 530. 



a. in., various forms of aster. 



2 i 2 



