6 



PORIPHORA. 



formed solely of horny threads; mouths not open- 

 ing in elevated warts. 



S. pulchella. 



Hmbata. Fig. 5*. 

 Isevigata. 



Dysidea (Johnston). Sessile, imperfectly cellu- 

 lar, shapeless, composed of a gelatinous membrane 

 containing particles of sand ; spicula few, of no 



certain figure. 



D. fragilis. 



papillosa. Fig. 6. 



5* 6 7 



Halisarca (Dujardin). Spreading as a thin 

 gelatinous crust on rocks and shells, semitrans- 

 parent, without spicula or distinct canals. 



H. Dujardinii. Fig. 7. 



Grantia (Flem.). Firm, inelastic, usually white, 

 variously formed ; texture close, "but porous ; 

 spicula calcareous, simple and starred; mouths 

 distinct. 



* Hollow. 



G. compressa. Fig. 8. 

 lacunosa. 

 ciliata. 



G. pulverulenta. 

 fistulosa. 

 botryoides. 



Incrusting. 



G. nivea. 



G. coriacea. 



