BRITISH SPONGIAD^. 5 



Type, Alcyoncellum, Quoy et Gaimard. Figures from Eu- 

 phctella aspergillum, Owen. Vol. I, Plate XXIX 

 Figs. 356, 357. 



5. Polymastia, Bowerbank. 



Skeleton. Basal mass. Central portion consisting of a 

 plexus of contorted anastomosing fasciculi, resolving 

 themselves near the surface into short straight bundles 

 disposed at nearly right angles to the surface. Oscula 

 congregated, elevated on numerous long fistulse. 

 Fistulae composed of numerous parallel fasciculi, 

 radiating from the base to the apex of each in straight 

 or slightly spiral lines. Vol. I, p. 177. 



Type, Polymastia mammillaris, Bowerbank. Vol. I, Plate 

 XXIX, Fig. 358. 



6. Halyphysema, Bowerbank. 



Sponge. Consisting of a hollow basal mass, from which 

 emanates a single cloacal fistula. Skeleton : spicula 

 of the base disposed irregularly; spicula of the fistula 

 disposed principally in lines parallel to the long 

 axis of the sponge without fasciculation. Vol. I, p. 

 179. 



Type, Halyphysema Thimanowiczii, Bowerbank. Vol. I, 

 Plate XXX, Fig. 359. 



7. CiocALYPTA, Bowerbank. 



Skeleton. Composed of numerous closed columns, each 

 consisting of a central axis of compact, irregularly 

 elongated, reticulated stricture, from the surface of 

 which radiate, at about right angles, numerous short, 

 simple, cylindrical pedicels, or stout fasciculi of closely 



