CHALINOPSILLA. Ill 



irregular branches are given off; these are always very thick, generally 

 compressed, more or less lamellar, terminating with wide, rounded, lobose 

 ends, or tapering to irregular slender points. The whole sponge attains a 

 height of 280 millim.; the breadth of the branches varies from 10-30 millim., 

 their thickness rarely exceeds 8 millim. and is generally 6 millim. The 

 surface is smooth and undulating. The concavities sometimes appear as trans- 

 verse incisions in the bi'anches, particularly in the bushy forms, which generally 

 have rather more cylindrical processes. In the flabelliform specimens these 

 concavities are not so deep and not nearly so well defined. 



The oscula are scattered irregularly over the surface of the stem and the 

 branches ; sometimes they are particularly numerous on the margin of com- 

 pressed branches, arranged in longitudinal rows, but scattered oscula are never 

 absent on the flat faces of these flabellar branches. The oscida are slightly 

 prominent, circular, and l'7-3 millim, wide, those of one and the same speci- 

 men are all fairly of the same size. 



The sponge is pretty hard and inelastic ; thick branches can, however, in 

 consequence of their size, be compressed between the fingers to one third of 

 their diameter. The colour of the living sponge is, according to Carter, " buff, 

 dark brown, or reddish orange"; according to Duchassaing and Michelotti, 

 " jaune un peu rose." 



The surface-sTceleton consists of a simple network of strings of foreign bodies, 

 O'l millim. thick, with irregular polygonal meshes 0-5 millim. wide. The 

 foreign bodies are small sand-grains, with an average diameter of 0'035. 



The supiwrting-skeleton consists of knotty parallel main fibres, 0'6 millim. 

 thick and 1'4 millim. distant, which contain large (0*25 millim.) scattered sand- 

 grains, which are on an average 0'13 millim. apart. The connecting-fibres 

 usually have two roots, but otherwise they are hardly at all branched ; they 

 generally contain an axial series of siliceous spicules, and are 0-08 millim. thick 

 and 1 miUim. apart. The spicules are longitudinally situat-ed oxea, 0*07 millim. 

 long and 0*006 millim. thick, intact or more or less fragmentary. 



Geographical Disteibution. — Gulf of Mexico : St. Thomas, Viecques 

 (^Duchassaing Sf Michelotti). 



South coast of Australia : Port Phillip Heads, V. {Wilson). East coast of 

 Australia : Port Jackson, N. S. W. (Lendenfeld). 



New Zealand : Port Chalmers (ParJcer). 



Chalinopsilla arborea, var, microporay Carter. 



Dactylia chaliniformis, H. J. Carter, " Descriptions of Sponges from the Neigh- 

 bourhood of Port Phillip Heads, South Australia," Annals and Magazine 

 of Natural History, ser. 5, vol. xv. p. 309 (1885). 



