228 



GEODIA. 



Sidonops nitida (Sollas). 

 Proc. Roy. Dublin soc, 1889, 6, p. 277. Lendenfeld, Tierroich, 1903, 19, p. 104. 



Synops nitidus Soll.\s, Proc. Roy. Dublin soc, 1886, 5, p. 198. Rept. voy. "Challenger," 1888, 25, p. 231, 

 plate 22, figs. 1-18. 



Lamellar, attenuated towards the margin. In spirit : faint brownish white. 



Aviphioxes: 1.25 mm. by 26 Orthoplagiotiiaenes: rhabdome 1.07 mm. 

 I)y 28.7 ft; clades 183 /j. long; cladome 358 pt broad, 50 n high. 



Choanosomal oxyasters: usually about seven, sometimes as few as two, 

 stout blunt rays with large spines; centrum small; total diameter, 43.4 /i. 

 Strongylosphaerasters: rays thick, tei-minally rounded; total diameter 13.5 jj.. 

 Sterrasters: spherical, 51. G /< in diameter. 



Southwestern Pacific. East coast of Australia; Port Jackson. 



GEODIA Lamarck. 



Among the megascleres are regular triaenes. The tetraxon megascleres 

 are confined to the superficial part of the sponge and arranged radially. The 

 dermal microscleres are asters. The afferents are cribriporal, the efTerents 

 cribriporal. 



Forty-four species are known, twenty-nine of which occur in the Pacific 

 Ocean. 



SUMMARY OF THE SPECIES FOUND IN THE PACIFIC OCEAN. 



A, Fully developed triaene mesoproclades (proclades) present. 



Ag The large choanosomal asters are oxyasters, rarely strongylasters, never 

 acanthtylasters. 

 A3 With sphacrasters up to 90 /< in diameter. 



G. nux (Selenka). 

 B3 The largest sphaerasters under 60 n in diameter. 



A4 With sphaerasters up to 31 in diameter, with very large centrum 

 and numerous very short and thick rays. 

 A5 The rays of the sphaerasters with large centrum are conic. 



G. eosaster (Sollas). G. globostella Lendenfeld. 

 B5 The rays of the sphaerasters with large centrum are cylindrical, 

 truncate, and bear terminal spines. 

 G. cUstincta Lindgren. 

 B4 Without large sphaerasters with very large centrum and very short 

 rays. 



