1867.] BR. J. K. GRAY ON SFONCES. 505 



Synopsis or Genera and Species. 



Section I, INfALACOsrouiE, or Sponges with soft spores or gcmmules. 

 Reproduction by ova contained in a thin membranaceous ovisac 

 not strengthened by sincules or by c/emnndes, scattered in the 

 substance of the sponge. 



These sponges are easily known by the absence of the hard sili- 

 ceous or siliceous- armed ovisacs that are to be found adundantly in 

 the substance of those of the following section. 



Subsection 1. Netted Sponges (Dictyospongi^). Skeleton formed 

 of a continuous siliceous or horny network. 



The fleshy part of the sponge is generally gelatinous and dried up, 

 leaving little to be observed in the dry sponges, and often easily 

 washed away. 



Order I. CORALLIOSPONGIA. 



Sponge hard, coral-like. Skeleton entirely formed of siliceous 

 spicules, anchylosed together by siliceous matter, forming a netted 

 mass covered with sarcode. 



The skeleton is formed of large siliceous spicules anchylosed to- 

 gether by siliceous matter. The sponges in which the siliceous ele- 

 ment is the most developed are siliceous sponges par excellence. 



Fam. 1. Dactylocalycid.e. 



Sponge massive, expanded or flabellate; the network with angular 

 meshes. 



LithospongicB, Duchass. & Michel. Spong. Carai'b. p. 25. 



This beautiful family of sponges is at once known by having the 

 skeleton formed of continuous anastomosing fibres formed of con- 

 centric lamina of silica, forming a hard brittle network. When alive 

 they are covered with a continuous external skin, which is pierced 

 with oscules on the upper and sometimes on the lower surface. 



As most of the species have been described at length in the * Pro- 

 ceedings of the Society,' I only give a synopsis of the genera for the 

 purpose of bringing them together in one view. 



* Netivorh irregular, not symmetrical. 

 1. Dactylocalyx. 



Bactylocalyx, Stutchbury, P. Z. S. 1841, p. SQ ; Bowerbank, R. 

 Sponges, i. p. 203 ; ii. p. 11 (Bactylochalix, Bowerbank, in B. M.) 



Iphyteon, Valenc. Institut. 



Sponge expanded, with large sunken grooves and oscules on the 

 upper and lower surface. Spicules of skeleton tuberculated ; spi- 

 cular network rugose, tubercular. Sarcode with scattered radiated 

 or stellate spicules, divided into branches near the base, and with 

 knobs at the tip of the rays. 



Sarcode studded with many-rayed stellate spicules ; the six piin- 



