504 ' vn. J. E. GRAY ON groNGEs. [JMay 9, 



Fani. 11. Clioniad.e. Spoii2;e living and making holes in shells, 

 corals, and limestone. Skeleton composed of pin-shaped fusi- 

 form and cylindrical spicules fasciculated together. Sarcode 

 granular. 



Order IV. ACANTHOSPONGIA. Spicules of more than one form 

 or kind in the same sponge. 



Fam. 12. ErpLECXELLAD.E. Sponge tubular. Skeleton composed 

 of longitudinal, transverse, and oblique bundles of spicules 

 intersecting each other and forming a network. Sarcode muci- 

 laginous, studded with many-rayed stellate spicules. 



Fam. 13. Esperiad.e. Sponge massive. Skeleton composed of 

 fusiform and linear spicules, interspersed with Jinchorate, biha- 

 mate, or birotulate spicules. Sarcode soft. 



Fam. 14. Tetiiyad/e. Sponge subglobular or massive. Skeleton 

 consisting of simple filiform spicules, with three prongs or three 

 recurved points at the outer end, and with more or less globular 

 many-rayed stellate spicules. 



Subsection 3. Sand Sponges (Arenospongi.e). Sponge consistinff 

 of a subcircuhn' disli of agrjlitiinated sand or siliceous spimla, 

 with a series of diverrjiiuj fliform spicules on the circumfer- 

 ence, and pencds of similar spicules on the mouth of the oscules 

 on the iqiper surface of the dish. 



Order V. ARENOSPONGIA. 

 Fam. 15. Xenospongiad.e. 



Section 11. CiiLAMYDOsroR^E (Sponges with armed spores). Repro- 

 duction by a thick ovisac, strengthened with siliceous spicules, 

 the ovisac often at length becoming solid spheres formed of si- 

 liceous spicules radiating from a central j^oint. 



Order YI. SPII/EROSPONGIA. Ovisac composed of closely 

 packed fusiform s])icules diverging from a centre, which, when 

 the ova are emitted, extend internally and fill up the cavity, 

 forming a nearly solid ball. 



Fam. 16. Geodiad^. Globose or subglobose, fleshy; the ovisac 

 forming a hard external coat. 



Fam. 17. Placospongiadje. Branched ; the ovisac forming a cen- 

 tral axis and external plates, separated by sarcode and fascicu- 

 lated spicules. 



Order YII. POTAMOSPONGIA. Ovisac coriaceous, strengthened 

 with various-shaped spicules placed on, or in the substance of, 

 the ovisac. 



Fam. 18, Spongillap^e. 



