S4 TETHTOEEHAPHIS. 



of thickness is observed ; the end then appears telescope-shaped. The margins 

 of the tufts are composed of et^yli measuriug 0'6x 0*015 millim. Some of 

 these are situated so that the pointed end lies centripetally ; most, however, 

 point their sharp end outward. The distal spicules project 0*l-0'2 millim. 

 beyond the surface. — (2) Stellate Microsclera. Globate stellates 0'056 millim. in 

 diameter, with pointed conic rays, not numerous, scattered throughout the 

 sponge, particularly in the canal-walls. — (3) Diact Microsdera. Very abundant, 

 forming a layer 0'03 millim. thick in the outer surface ; rough, 0-012 x 0'002 

 millim., mostly straight, sometimes curved or bent in an angular manner. 



Geographical Disteibution. — East coast of Australia: Port Jackson, 

 N. S. W. {Ramsay , Lendenfeld). 



Tethyorrhaphis gigantea, n. sp. 



Spherical sponges, attached by a small base, covered with monticular projec- 

 tions, which are separated from each other by irregular depressions. Height 

 60-90 millim.; breadth 50-70 millim. The superficial projections are raised 

 8 millim. over the depressions. Surface regularly tuberculose. The tubercles 

 higher on the elevated parts than in the depressions ; 2-5 millim. broad and 

 from 1"2 millim. high. Oscula very small, few in number, mostly on the 

 upper side of the sponge. Alive intensely orange-red on the surface ; of a 

 lighter colour in the interior; in spirit light yellow. Cortex 3-4 millim. thick. 

 Eadially compressed and irregular tangential canals are found in the cortex 

 just below the outer surface ; they are divided from the outer water by a 

 very thin perforated membrane. The pores are arranged in zones following 

 these superficial canals, and measure 0"06 millim. in diameter. 



Skeleton. — Central sphere 4 millim. in diameter. Eadiating spicule-bundles 

 further apart than in any other species (4 millim.), 0-5-0*7 millim. thick, 

 expanding only slightly in the surface-tufts. — (1) Monad Megasdera. 

 Strongyla, spindle-shaped, 2 x 0*035 millim. ; thickest portion much nearer 

 the blunter end, which is usually situated centripetally, and about 2| times 

 as thick as the other. The rounded ends are slightly inflated. There are 

 no monact cortical spicules round the surface-tufts. — (2) Stellate Microsdera. 

 Of three kinds: — (A) Globose stellates, with conical pointed rays, 0*07 

 millim. in diameter ; in the outermost portion of the pulpa and along 

 the cortical canals. (B) Small stellates, with slender cylindrical terminally 

 thickened rays ; scattered throughout the pulpa, not numerous. (C) Small 

 stellates, with slender, rough cylindrical rays, which are often not of uniform 

 length, and in other ways irregular; measuring 0*02 millim. in diameter. 

 These spicules are likewise scattered throughout the sponge ; they are very 

 rare in the cortex. — (3) Oxeoie Microsdera. Scattered sparsely throughout 



