22 lANTHELLA. 



Tamilia DARWINELLIDiE. 

 Hexaceratina with horn-fibres and with horn-spicules. 



Familia APLYSILLID^. 

 Hexaceratina with horn-fibres, but without horn-spicules, 



Geuus lANTHELLA. 



Aplysilhdse with cellular cavities in the spongin-wall of the 

 horn-fibres. 



lanthella concentrica, Hyatt. 



lanthella concentrica, A. Hyatt, " Revision of the North American Poriferae, 

 with Remarks upon Foreign Species. — Part 1.," Memoirs of the Boston 

 Society of Natural History, vol. ii. (1875). 



lanthella concentrica, !F. E. Schulze, " Uutersuchungen iiber den Bau unci die 

 Entwicklung der Spongien. — IV. Mittheilung. Die Familie der Aplysi- 

 nidae," Zeitschrift fiir wissenschaftliche Zoologie, Band xxxv. Seite 385 

 (1878). 



This sponge presents the shape of a regular cup which is attached by a com- 

 paratively broad base ; it attains a height of 150 millim. and has a circular 

 margin 110 millim. in diameter. The shape of the cup is that of a cone. 

 Just below the margin the wall of the cup is 10 millim. thick, it becomes 

 thicker further down. The surface is rendered uneven by the projection of 

 very irregular broad and low conuli, \\hich are on an average 8 millim. apart 

 and 2-3 millim. high. The external and the internal surface of the cup 

 present the same appearance. The oscula are confined to the inner side of the 

 cup ; they are circular, and 1-5-3-5 millim. wide ; rare and small near the 

 margin of the cup, they become larger and more numerous towards the base. 



The skeleton consists of a very irregular network of immensely thick 

 fibres. The meshes of the network are 10 millim. wide and the fibres are 

 1 millim. thick. Of all the sponges known to me, this has the thickest fibre. 

 The sponge, when dry, is of a dark blue colour ; it is very hard, and quite 

 incompressible. 



Geographical Disteibution. — West coast of Australia, Western Australia 

 {Baily). 



Fiji {Hijnit). 



