508 DR. J. E, GRAY ON SPONGES. [May 9, 



Order II. KERATOSPONGIA (Horny Sponges). 



Sponge elastic. Skeleton formed of horny netted fibres, generally 

 without, but sometimes more or less strengthened with, minute sili- 

 ceous spicules or grains of sand. 



These are the horny sponges par excellence, the skeleton con- 

 sisting of horny fibres, more or less strengthened by siliceous spicula, 

 which are generally of a small size. 



Bictyospongi(B, Duchassaing & Michelotti. 

 Spongia heratosa, Bowerb. B. Sp. 



Fam. 3. Spongiad^. 



Skeleton formed of one kind of reticulated horny fibres, not en- 

 closing any spicules or sand. 



EuspongicB, Duchassaing & Michelotti, I. c. p. 25. 



* Fibres of skeleton solid, homogeneous. 



1. Spongia, Linn. 



Sponge irregularly netted. Fibres of skeleton solid, cylindrical, 

 without spicules, very elastic, and nearly of equal thickness. 



Spongia, Nardo, Isis, 1833, p. 321 ; Bowerb. B. Sp. i. p. 205 ; 

 O, Schmidt, Spong. Adriat. Suppl. ii. p. 9. 



Eiispongia, Bronn. 



Spongia officinalis. B.M. 



Spongia officinalis, Nardo, Isis, 1833 ; Bowerb. B. Sp. i. p. 205, 

 t. 37. f. 379, t. 13. f. 261. 

 See also — 



S. quarnerensis, O. Schmidt, I. c. p. 22, t. 2. f. 2, t. 3. f. 1. 

 S. dmocca, O. Schmidt, /. c. p. 23, t. 2. f. 3, 4. 

 S. equina, O. Schmidt, I. e. p. 23, t. 2. f. 5. 

 S. mollissima, O. Schmidt, ^. c. p. 23. 



2. Spongionella. 



Sponge symmetrical, very elastic, netted ; the primary fibres 

 thicker, radiating ; secondary thinner, horizontal. 



Spongionella, Bowerbank, B. Sp. i. p. 20ti ; O. Schmidt, Spong. 

 Adriat. Suppl. ii. p. 9. 



Spongionella pulchella, Bowerbank, B. Sp. i. p. 206, t. 37. 

 f. 380 ; ii. p. 359. B.M. 



Spongia pulchella, Sow. Brit. Misc. p. 87, t. 43 ; Johnson, B. S. 

 p. 167, t. 19. f. 1, 2. 



Cacospongia scalaris, 0. Schmidt, Spong. Adriat. p. 27, t. 2. 

 f. 4. 



Hab. British Seas. 



