AULENA. 231 



fresh state the sponges are soft and resilient, iu the dry state hard and inelastic. 

 The tubes which lead from the surface to the central cavity, together with the 

 atter, are to be considered as vestibular lacunae. On the surface of the honey- 

 comb-like lamellee groups of inluilant pores and oscula are scattered indiscri- 

 minately. The inhalant pores lead into irregular subdermal cavities, which 

 appear as tangential canals 0-12 millira. wide. The inhalant and exhalant 

 canals are, on an average, 0*05 millim. wide. The ciliated chambers are sphe- 

 rical, 0-025 millim. wide, and open direct into the exhalant canals. The efferent 

 pore is about one fourth as wide as the chamber. 



Dermal sheleton : siliceous spicules are scattered irregularly in the skin ; 

 0*2 millim. below it a network of stout fibres extends parallel to the surface. 

 The fibres forming this network are on an average 0*1 millim. thick, and cored 

 with an axial series of large sand-grains. They contain no siliceous spicules, 

 and are not echinated. From their outer side short fibres arise which extend 

 perpendicularly to the surface, and appear to consist of fragments of foreign 

 siliceous spicules, cemented by a small quantity of spongin. These fibres are 

 generally slightly branched, the branches tending upwards and abutting per- 

 pendicularly on the surface. They are 0'03 millim. thick, and echinated by 

 projecting styli, which are given off at an angle of about 45°, and point out- 

 ward. The supporting skeleton consists of a network of longitudinally- 

 extending, irregular, and much curved anastomosing main fibres, which are 

 0-12-0-14 millim. thick, and, similarly to the fibres of the tangential net- 

 work, cored with a single series of sand-grains. The connecting-fibres are 

 0*04-0-06 millim. thick, and generally extend, without branching, from one 

 main fibre to another. In the interior of the sponge no spicules of any kind 

 are found. Those scattered in the surface are partly foreign, like those which 

 are found in the axes of the echinated fibres. Among them strongyla, 0*14 

 millim. long and 0-002 millim. thick, are frequent. The spicules which echinate 

 the fibres are conical styli 0*07-0-09 millim. long, and at the base 0-02-0-03 

 millim. thick. 



This species resembles certain forms of Ectyoninse, particularly of the genus 

 Chdhriopsamma, so closely that I do not hesitate to consider them closely 

 allied. 



Aulena gigantea, var. macropora, Lendenfeld. 



Hahne gigantea, var. macropora, E. v. Lendenfeld, " Second Addendum to the 

 Monograph of the Australian Sponges," Proceedings of the Linnean 

 Society of New South Wales, vol. x. part 4, p. 850 (1886). 



Hohpsamma laviinccfavosa (partim), H. J. Carter, " Descriptions of Sponges 

 from the Neighbourhood of Port Phillip Heads, South Australia," Annals 

 and Magazine of Natural History, ser. 5, vol. xv. p. 212 (1885). 



