446 Dr. J. E. Gray on the Classification of Sponges. 



subscription among scientific men ; and I could refer to several 

 cases where such were hardly known before they received 

 similar symjDathy, whatever might have been the cause of 

 their distress respectively. 



Section A. THALASSOSPONGIA. (Marine Sponges.) • 



Sponge marine, brown, red, or purple. Ova membranous, 

 unarmed. 



Subsection 1. Leiospongia, Gray, P. Z. S. 1867. 



Sponge horny, without any spicules, or, when spicules are 

 present, they are of the most simple kind, being either fusi- 

 form, needle-shaped, or pin-shaped, often varying in size in 

 the same species, and sometimes strengthened with sand and 

 other extraneous bodies. 



Order I. KEHATOSPONGIA. 



Sponge consisting of horny fibres, often anastomosing and 

 more or less elastic ; sometimes purely horny, at others 

 strengthened with grains of sand, broken spicules, or siliceous 

 spicules, either enclosed in the centre of the fibres or scattered 

 on the surface. The thickness and solidity of the horny coat 

 vary in different families ; sometimes it is very thick and 

 hard, and at others it scarcely covers the spicules with a very 

 thin coat. 



A. The skeleton of the sjyonge horny or only strengthened hy 

 grains of sand or foreign spicules borrowed from the sand. 



Fam. 1. Spongiadse, Gray, P. Z. S. 1867, p. 508. 

 Skeleton formed of reticulated horny fibres. 



a. The fibres of the skeleton homogeneous. Spongia^ 8p)on- 

 gionella, Cacosjyongia, Phyllosjjongia (Eihlers). 



b. The fibres of the skeleton surrounded by a soft cortical 

 substance. Aj)lysina. 



c. The fibres with a central tube. Verongia, lanthella (Gray) . 



Fam. 2. Ceratelladse, Gray, P. Z. S. 1868, p. 575. 



Sponge irregularly dichotomously branched; stem hard, 

 solid, dilated at the base, with abundance of very minute, 

 cylindrical, tortuous tubes ; branches and branchlets tapering, 

 formed of very tortuous cylindrical fibres forming loops, which 

 produce a spicular surface. 



Ceratella SindDehitella, Gray, P.Z. S. 1868, p. 579, figs. 1,2. 

 Auliskia appears to be a sponge-fibre on which a horny 



