Sollas — On Tetractinellid Sponges. 191 



0-035 mm. ; (2) fork, shaft, 2*1 by 0-047 mm. ; arms, simple, 

 0-35 mm. long ; (3) anchor, shaft, 3-5 by 0-024 mm. ; rays, 

 0-075 mm. long ; (4) minute acerate of oscular margin ; (5) chias- 

 ter, 0'009 mm. in diameter in the ectosome, 0*012 mm. in choano- 

 some. 



Habitat. — Torres Straits. 3-11 fms. 



Genus 3. Anthastra, g. n. — Sponge usually more or less 

 spherical ; oscules distinguishable from the pores or not ; ectosome 

 thin, chiefly collenchymatous, excavated by extensive sub-dermal 

 cavities which never form chones ; choanosome as in Myriaster. 

 Flesh spicules an anthaster and usually a chiaster. (The anthaster 

 is a stellate with conical or bacillar microspined rays, which may 

 be numerous but are usually few in number, and may be reduced 

 to two, when a spined bacillus is the result.) Distribution : 

 Australian seas, and Japan. 



Anthastra communis, sp. n. — Sponge more or less spherical, free 

 or attached ; oscules not distinguishable from the pores. Spicules 

 —(1) acerates 4-2 to 5-6 by 0-06 to 009 mm. (2) fork with bifur- 

 cated arms, primary rays projecting forwards and outwards, some- 

 times more outwards than forwards, sometimes the reverse, then 

 giving the head a cyathi-form appearance, secondary rays horizon- 

 tal, shaft, 4-4 to 5*7 by 0-09 to 0-1 1 mm. ; primary rays, 0-14 to 

 0-16 ; secondary, from 0*52 to 1-114 mm. long ; (3) anchor, shaft, 

 3*0 to 4-3 by 0-32 to 0'39 mm. ; rays, 0-127 to 016 mm. long. ; 

 (4) anthaster, rays few, 0*02 to 0-03 mm. long; (5) chiaster, spines 

 numerous, 0-006 to 0-008 mm. long ; colour, greyish-white, some- 

 times russet-red (owing to presence of algal cells ?). 



Habitat.— Station 162, lat. 39° 10' 30" S. ; long. 146° 37' E.; 

 38 fms. Station 162a ; lat. 36° 59' S. ; long. 150° 20' E. ; 150 

 fms. Port Jackson, 6 to 15 fms. 



Anthastra pulchra, sp. n. — Sponge small, globular, free, a single 

 oscule. Spicules — (1) acerate, 2*4 to 3-1 by 0*0315 mm. ; (2) fork 

 with simple arms, shaft, 2 # 6 to 2-9 by 0-0474 mm. ; arms, 0-26 

 mm. long ; (3) anchor, shaft, 2*6 to 2*9 by 0-0315 mm. ; rays, 

 0*125 mm. long; (4) anthaster, rays few, 0-016 mm. long; 

 [5] chiaster, variable in character, rays seldom capitate. 



Habitat.— Station 163 a.; lat. 36° 59' S. ; long. 150° 20' E. 

 150 fms. 



