SPONGES. 241 



(89.) Toi'Sknt. " yuol(|iirs Spongiaires du Banc de Campeche et de la Pointe-a-Pitre." ' Mem. Soc. Zool. 



de Franco,' tome 2. 1889. 

 (90.) THURSTON. "Ram&varam Island and Fauna of the Gulf of Manaar." 'Madias Government 



Museum,' Bulletin No. 3. 1895. 

 (91.) TijI'sknt. " Eponges de la Mer Rouge." ' Mem. Soc. Zool. de France,' tome v. 1892. 

 (92.) Topsent. "Note sur quelques Eponges du Golfe de Tadjoura." 'Bull. Soc. Zool. de France,' 



tome xviii. 1893. 



DESCRIPTION OF PLATES. 



PLATE I. 



Fig. 1. HexadeUa indica ; vertical section of R.N. 46, combined drawing. 



111., inhalant chones ; I'LL., choanosomal lamella; Or., sub-cortical crypts; Eel., ectosome ; 

 F.C., flagellate chambers; L.E.C., larger exhalant canal; Mem., roofing membrane of 

 inhalant chones; P.E.I '., primary exhalant canals; P.I.C., primary inhalant canals; 

 Sy.J., symbiotic algse. 

 ,, 2. Hexadella indica ; small portion of vertical section through choanosomal lamella, more highly 

 magnified (Zeiss F., Oc. 2). 

 C.T.C., connective-tissue cells; Ep., epithelium lining primary inhalant and exhalant canals; 

 I.I'd., inhalant canaliculi. (Other lettering as before.) 

 ,, 3. Hexadella indica : tangential section of the ectosome, seen from below, showing the inhalant 



chones, &c. x 52. (Lettering as before.) 

 ,, 4. Plakinastrella intermedia : R.N. 224. x 2. o., vent. 

 ,, 5. Ecionema carteri; R.N. 175. x 2. o., vents; j>..s., pore-sieves. 

 ,, C. TeiUla poculifera ; R.N. 230. x 3. Upper part in section. 



67., cloaca; L.E.I'., larger exhalant canals. 

 7. TetUla limicola ; R.N. 70. Nat. size. 



p., vents ; r.t., root tuft of spicules matted together with mud. 

 8. Taprobane herdmani; R.N. 40. Slightly reduced ; from a photograph. 



PLATE II. 



Fig. 1. Dercitopsis ceylomka; R.N. 139. Spicules. All x 230. 

 a.-h., calthrops and triods ; i.-o., oxea. 

 2. Plakinastrella intermedia ; R.N. 224. Spicules. 



a.-d., dichotriames, x 52 ; e.-n., oxea, x 52 ; o.-p., microxea, x 230 ; </.-"., oxyasters, x 230. 

 3. Plakinastrella sch / zei ; R.N. 149. Spicules. 



a.-d., triames, x52; c-q., oxen, x 52 ; r.-t., microxea, x230; u.-.c, oxyasters, x 230. 

 4. Pilochrota haeckeli'; R.N. 127. Spicules. All x 52. 



a., orthotrisene ; /., monstrous form of orthotriwne; c, anatriajne ; ('., e., monstrous forms of 

 anatriajne. 

 ,, 5. Pilochrota hornelli; R.N. 176. Spicules. 



a., /'., orthotria'.nes, x 52 ; <., '/., cladomes of orthotria-nes seen from above, x 52 ; <'., anatriajne, 

 x 52 ; /., oxeote, x 52 ; g.-i., chiasters, x 230. 

 ,, 6. Stelletta herdmani ; R.N. 137. Spicules. 



a.-'., trhrites, x 52 ; '/., oxeote, x 52 ; e.-h., chiasters, x 230 ; i.-k., oxyasters, x 230. 

 7. Stelletta vestigium ; R.N. 200a. Spicules. All x 230. 



*'.-/., reduced triaenes ; e., oxeote; /., </., spherasters; //.. /.. oxyasters. 



2 I 



