BY R. VON LENDENFELD, PH.D. 1127 



smooth. The Sponge attains a length of 30 and a diameter of 

 12 mm. The Gastral cavity is cylindrical and rather narrow, 

 measuring only a third of the diameter of the Sponge across. The 

 thick body wall is lacunar; wide canals measuring from 0*2 — 

 0*25 mm. in diameter, and with a circular transverse section, 

 traverse it in every direction. Below the outer surface we meet 

 with extension, communicating sub-dermal cavities, from which 

 comparatively narrow canals take their origin, which can be 

 traced in a centripetal direction for some distance. The circular 

 Canals mentioned above belong to the exhalent canal system, and 

 are connected with the Grastral cavity by very wide (0-4 mm.) and 

 irregular tubes, whijh do not stand vertical in the Gastral wall, 

 but extend upwards towards the Osculum. The pores in the 

 Gastral wall at their terminations are scattered sparsely, and 

 measure on an average 0-5 mm. across. The ciliated chambers 

 have a diameter of 0*06 mm. 



Spicules : The skeleton consists mainly of triradiates in the 

 Parenchyma. The Gastral quadriradiates are small and 

 irregularly scattered ; the rays and angles are all different. The 

 rays vary from 0028—008 x 0-004—0-007. The Parenchymal 

 Triradiates are very regular ; sometimes the rays are slightly 

 bent; they are conic and blunt and measure 035 x 001. 

 Acerates of the Parenchyma, more or less radially disposed, 

 pointed at both ends, slightly protruding beyond the surface, 

 spindle-shaped, and measuring 1"5 and 0-035 mm., rather rare. 

 Minute Acerates in a continuous layer in the outer surface all 

 parallel and situated radially, measuring 0-08 x 0002. These 

 spicules are rounded at the proximal, and pointed sharply at the 

 distal end. Although forming a continuous layer, they nerver- 

 theless do not produce a dense and hard outer skin as in those 

 Sponges which possess a " Stabchen-Mortel." Acerates forming 

 the frill named the Osculum of the same appearance as the 

 former, measuring 0*3 — 5 x 0-002 often slightly bent. Thickest 

 towards the proximal rounded end, and tapering from there to 

 the distal end, which is mostly broken off in specimens. 



Locality : East Coast of Australia, Port Jackson, Laminarian 

 zone. Von Lendenfeld. 



