242 KEY TO TIIE AUSTBALIAK GENBEA. 



'^ With stellate microsclera. (Tethydae.) .... 23 



Without microsclera, with chouse. (Sollasel- 

 lidae.) (24) 



With spined, spiral or irregular microsclera. 

 (14) < (Spirastrellidae.) (25) 



With smooth sigmate microsclera. (Subera- 

 matidge.) 



Without microsclera and without chonse. 



(Suberitidse.) (26) 



With stellates only Tethya, p. 46. 



(25) { 



23 



With stellates and small rods Tethyorrhaphis,p.52. 



(24) Sponges digitate SoUasella, p. 56. 



Sponges massive, solid, with pretty smooth ! 



surface Spirastrella, p. 57. 



Sponges cavernose, with tubercles on the sur- 

 face. Microsclera stout spined strongyla . . Papillina, p. 58. 



Sponges regularly honeycombed Raphyrus, p. 60. 



Sponges very cavernose, with tubercular pa- 

 pillae on the surface. Microsclera very 

 [_ abundant ; slender spined oxea Papillissa, p. 64. 



f Sponge massive or digitate Snberites, p. 65. 



J Sponge reticulate. Plectodendron, p. 66. 



(2d) <; 



I Sponge lives in tubular cavities excavated in 



L shells Cliona, p. 67. 



(15) 



With stout stellate microsclera Chondrilla, p. 68. 



Without spicules of any kind Chondrosia, p. 72. 



Freshwater sponges with gemmulse. (Spon- 



(8) \ gillidae.) 27 



Marine sponges without gemmulae ........ (28), p. 243. 



r 



Gemmulse surrounded by spined oxea Spongilla, p, 74. 



Gemmulso surrounded by amphidiscs with 

 27 ^ unequal terminal discs Tul)ella, p. 75. 



} Gemmulae surrounded by amphidiscs with 



I equal terminal discs Meyenia, p. 76. 



