4 A MONOGRAPH OF THE 



short fasciculi of siliceous spicula, disposed in lines at 

 about right angles to the surface of the sponge. 

 Central portion of the sponge unsymmetrical. Dermis 

 crustular, furnished abundantly with closely packed 

 ovaria. Ovaria siliceous, formed of cuneiform spicula, 

 firmly cemented together in lines radiating from the 

 centre of the ovary. Pores furnished with oesophageal 

 tubes, terminating in the distal extremity of each 

 intermarginal cavity. Intermarginal cavities sym- 

 metrical, subcylindrical, with a pyloric valve at the 

 proximal end of each. Vol. I, p. 171. 



Type, Pachymatisma Johnstonia, Bowerbank. Vol. I, 

 Plate XXVII, Pig. 353. 



3. Ecionemia, Bowerbank. 



Sponge. Having a strong axial column or centre of closely 

 packed siliceous spicnla disposed in lines parallel to 

 the long axis of the sponge, from which axial column 

 or centre a peripheral system of spicula radiates at 

 about right angles. Distal ends of the radii fur- 

 nished more or less with ternate connecting spicula, 

 the radii of which are disposed immediately beneath 

 the dermal membrane. Vol. I, p. 173. 



Type, Echionemia acervus, Bowerbank, MS. Vol. I, 

 Plate XXVIII, Pig. 355. 



4. Alcyoncellum, Qhoj/ et Gaimard. 



EtJPLECTELLA, Owen. 



Sponge fistulate ; fistula single, elongate, without a massive 

 base. Skeleton : primary fasciculi radiating from the 

 base in parallel straight or slightly spiral lines ; secon- 

 dary fasciculi at right angles to the primary ones. 

 Oscula congregated, with or without a marginal 

 boundary to their area. Vol. I, p. 174. 



