CHALINOPSILLA. 107 



Chalinopsilla imitans, Lendenfeld. 



Chalinopsis imitans, E. v. Lendenfeld, " Studies on Sponges. — IV. On two 

 cases of Mimicry in Sponges," Proceedings of the Linnean Society of New 

 South Wales, vol. x. pp. 569, 570 (1886). 



This large and elegant species imitates Dactylochalina cylindrica very closely. 

 The sponge consists of a number of very regular digitate branches, which 

 grow out from a short and stout stem, expanded below and firmly attached 

 to the sea-bottom. It is about as long as thick, and tapers towards the 

 upper end, from which the branches grow out. There are two or three 

 branches which deviate at an angle of about 45° from the perpendicular. 

 From the upper side of these laterally extending branches a number of up- 

 right processes are given off, which are only very slightly ramified, and 

 which stand erect and are parallel to each other. When these vertical pro- 

 cesses appear branched, the main branch does not deviate from its direction, 

 although it is not thicker than the other branch. The upright processes are 

 digitate, regularly cylindrical, and have a smooth surface ; they are slightly 

 bent in an undulating fashion, and taper terminally to a narrow conic end. 

 The sponge attains a height of 600 millim., and the branches are 8 millim. 

 thick. The stem has a thickness of 15-20 millim. The oscula are small and 

 scattered over the whole of the surface ; they measure only 0*6 millim. in 

 diameter, and easily escape observation. The dry skeleton is light grey. The 

 sponge is very hard and uncompressible. 



The surface-sl'eleton consists of a network of primary superficial fibres, 

 which are, on an average, 0*16 mUlim. thick ; between these a network of 

 secondary fibres 0"06 millim. thick is spread out. 



The supporting -skeleton consists of longitudinal main fibres, with an average 

 thickness of 0*4 millim., and unbranched connecting-fibres 0'35 millim. thick, 

 which are perpendicular to the main fibres. In the main fibres of the 

 supporting-skeleton, and also in the primary fibres of the surface-skeleton, 

 scattered small foreign bodies (sand-grains, with an average diameter of 0-04 

 millim.) are met with. 



Geogra-PHical Distribution. — East coast of Australia : lUawarra, IV. S. W. 

 {Ramsay). 



Chalinopsilla dichotoma, Lendenfeld. 



Chalinopsis dicliotoma, E. v. Lendenfeld, " Studies on Sponges. — IV. On two 

 cases of Mimicry in Sponges," Proceedings of the Linnean Society of 

 New South Wales, vol. x. p. 570 (1886). 



The sponge is erect and branched, with digitate, more or less upright, and 



