18G7.] DR. J. E. GRAY ON SPONGES. 509 



3. Cacospongia, O. Sclimidtj Spong. Adriat. 27. 



Skeleton composed of hard, rather elastic, homogeneous fibres of 

 unequal thickness. 



1. Cacospongia mollior, 0. Schmidt, p. 27. B.M. 

 Ilab. Adriatic. 



2. Cacospongia cavernosa, O. Schmidt, p. 28. B.M. 

 Hah. Adriatic. 



4. SiPHONiA, Blainv. Man. Act. p. 536. 



Sponge polymorphic, with a central apical aperture or cloaca, with 

 large longitudinal and smaller transverse canals ; composed of dense 

 fibres. 



SiPHONiA TYPUM, Blaiiiv. Man. Act. p. 536, t. 9ii. f. 1. 



Hab. Sicily. B.M. 



** Fibres of one land, the more solid axis being surrounded by a 

 softer cortical substance 1 



5. Aplysina, 0. Schmidt, Spong. Adriat. p. 25. 



Sponge fleshy ; fibres of one kind, slightly elastic, consisting of a 

 solid axis, surrounded by a softer bark. 

 Aplisia, Nardo, not Linn. 



1. Aplysina aerophoba, Nardo; O. Schmidt, p. 25, t. 3. f. 2. 

 Hah. Adriatic. B.M. 



2. Aplysina carnosa, 0. Schmidt, p. 26, t. 3. f. 3. 

 Hah. Adriatic. 



*** Fibres with a central tube, 



6. Verongia. 



Sponge irregularly netted ; the fibres with a central canal, without 

 spinules. 



Verongia, Bowerbank, Ann. & Mag. N. IL xvi. p. 400, 1845; 

 Brit. Sp. i. p. 209; O. Schmidt, Spong. Adriat. Supp. ii. p. 10. 



Aplysia, Nardo, 1854. 



Aplysina, Nardo, 1844, 1862; O. Schmidt, Spong. Adriat. 



1. Verongia fistularis, Bowerb. B. Sp. i. p. 209, t. 13. f. 266. 

 Spongia fistularis, Lamk. 



2. Verongia zetlandica, Bowerb. B. Sp, ii. p. 280. 

 Hah. Zetland. 



