HIPPOSPONGIA. 139 



on an average 0-3 millim. apart, straight or gracefully curved, appearing like 

 ropes suspended from the upright main fibres. They are not bent at the 

 joining points with the secondaries, rarely divide into two roots where they 

 join the main fibres, and are generally perfectly simple and not at all branched. 

 They extend in a trumpet-shaped manner at the base, where they join the 

 main fibres, and measure on an average 0*03 millim. in thickness. The thick- 

 ness, however, is proportional to the length, inasmuch as the longer fibres are 

 always thicker than the shorter ones. 



Many of the secondary connecting-fibres are quite simple and connect, 

 extending in a more or less radial direction, the primary connecting-fibres with 

 each other. They are generally perpendicular to the primaries. Many are 

 ramified, and they altogether form an irregular network of fibres of varying 

 thickness, which connects the primaries. The thickness of the secondaries 

 varies from O'Ol to 0'02 millim. ; they are attached to the primaries by broad, 

 trumpet-shaped extended bases. 



Geographical Distribution, — East coast of Australia : Port Jackson, 

 N, S. W. {Ramsay). 



Hippospongia canaliculata, var. elastica, Lendenfeld. 



Euspongia canaliculata, var. elastica, E. v. Lendenfeld, " A Monograph of the 

 Australian Sponges. — Part VI. The Genus Euspongia," Proceedings of the 

 Linnean Society of New South Wales, vol. x. p. 502 (1885). 



The main fibres are slightly and gracefully curved, and taper more abruptly 

 towards their ends than in the foregoing variety. They have a smooth surface, 

 measure 0-1 millim. in thickness, and are a little closer together than in other 

 varieties. They contain axial foreign bodies, chiefly sand-grains, which, 

 however, are not near so numerous as in E. c. dura. 



The connecting-fibres are not so distinctly differentiated into primaries and 

 secondaries as in the variety above described. The primaries are on an average 

 0*4 millim. apart and angularly bent at the joining points with the secondaries. 

 They do not appear as graceful curves pendent between adjacent main fibres, 

 but rather as broken lines, composed of longer or shorter, straight portions 

 which are joined at angles approaching very closely to 180°. They measure 

 0"028 millim. in thickness. Also here we find those which extend between 

 distant main fibres thicker than those which join main fibres more close 

 together. The secondaries are rarely simple, they generally ramify and anas- 

 tomose to form a regular network, the meshes of which are 0*3 millim. wide. 

 The thickness of the secondaries varies from 0-005 to 0*025 millim. ; the very 

 thin ones are rare ; the intermediate ones most numerous. As the primaries 

 are bent at the joining points and the secondaries approach the thickness of 



