Plate 48 



Fig. 1. Trickostemma straticulatum. Median section, a. r. b., ascending 

 radial skeletal bundle; ch, choanosome ; fr. s., fringe spicules; 

 1. c. m., middle stratum of lower cortex ; o. c, oscular canal : 

 u. c. m., middle stratum of upper cortex. X7!/£. 



2. Strong ylophora corticata. Skeletal spicules, a, strongyle; b, oxea 



X225. 



3. Spongo8orite8 suluensis. Vertical section through the lamellate 



sponge, n. e., natural edge ; o. s., oscular surface ; /;. *., pore 

 surface. X7i/>. 



4. TetiUa (Cinachyrella) paterifcra. Anatriaene forms, a, common 



form seen in optical section ; 6, aberrant form with very short 

 rounded clads ; c, monaene form ; d, tylostyle form ; c, aberrant 

 form with very short rounded clads and rhabdome produced be- 

 yond the cladome (anamesotriaene type). X4."i<). 



5. TetiUa {Cinachyrella) crust at a. From a section vertical to the sur- 



face. 0-6, thickness of ectosomal layer of tangential oxeas. X160. 



6. Paratctilla arcifera. From a radial section. X45. 



7. Strong ylophora corticata. Spicules of mierosclere size, a, small 



stout strongyle; b, small slender strongyle; c, characteristic an- 

 gulated microxea ; d, microstrongyle, a rare form ; e, nearly 

 straight microxea: /, very slender oxeas curved much like toxas 

 hut without the recurved ends of the latter. X650. 



8. Petrosia testudinaria, var. fistitloyltora. a. skeletal spicule, an oxea, 



of specimen from station f>2r>4 ; h, skeletal spicule, an intermediate 

 with tapering ends rounded at the extremity, of specimen from sta. 

 t;-_\-»3. XI 50. 



9. Petrosia lignosa. Spicules, a, strongyle with broadly rounded ends 



from specimen taken at station 5250. Other spicules from speci- 

 men taken at station 5147. ft, intermediate (oxea with rounded 

 ends); c, e, oxeas; d, style (a rare form); f, small strongyles. 

 X150. 



10. Phloeodictyon cagayanensc. Spicules: oxeas, one more abruptly 

 pointed than the other, and strongyle. X400. 



518 



