1872.] DR. J. S. BOWERBANK ON THE SPONGIADJ3. 123 



containing an irregularly disposed series of spicula ; secondary- 

 series of fibres unsymmetrical, cylindrical, without spicula. 



With further experience of the sponges coming under this de- 

 signation, I have in many cases found that the primary fibres fre- 

 quently contained a mixture of spicula and sand, and that the latter 

 often predominated in quantity as in the skeleton-fibre of the sponge 

 in course of description. Hereafter perhaps, from the regularity of 

 the fibrous skeleton structure and the prevalence of sand in its pri- 

 mary fibres, it may be advisable to refer it to a new genus ; but for 

 the present I have thought it as well to retain it in the genus Hali- 

 spongia. 



Halispongia choanoides, Bowerbank. 



Sponge massive, subspherical, pedicellate ; pedicle short and stout, 

 branching into radical processes. Surface irregularly and coarsely 

 reticulated ; rete forming large elevated ridges ; areas deeply de- 

 pressed and minutely reticulated. Oscula within a large cylindri- 

 form cloaca, extending from near the base to the apex of the sponge, 

 terminating in a wide permanent simple orifice. Pores inconspi- 

 cuous, congregated in irregular areas. Dermis coriaceous, stout ; 

 surface abundantly furnished with minute granules of sand ; dermal 

 membrane thin, pellucid. Skeleton symmetrical ; rete stout ; pri- 

 mary lines with axes of sand, spicula, and other extraneous matters ; 

 secondary lines without extraneous matters ; areas square or oblong. 

 Sarcode abundant, firm, and fleshy. Gemmules large, lenticular ; nu- 

 cleus radiated. 



Colour in spirit dull purple. 



Hub. Fremantle, Australia (George Clifton, Esq.). 



Examined from spirit in the state in which it came from the sea. 



I am indebted to my indefatigable and liberal friend Mr. George 

 Clifton for this very remarkable specimen, which he sent in spirit 

 from Fremantle. The skeletons of what are apparently various spe- 

 cies of this genus are very common in collections of sponges from 

 Australia ; but the one in course of description is the only specimen 

 I have seen in a state of perfect preservation as it exists during 

 life. The form of the present specimen, closely approaching sphe- 

 rical, will probably be found hereafter to be subject to considerable 

 variation, as this is the case with many of the closely allied speci- 

 mens in the skeleton state, some being elongately oval and some 

 inversely conical. The skeleton is formed of an open network of 

 large and strong keratose fibres that are quite visible to the unas- 

 sisted eye when separated from the abundant sarcode in which 

 they are imbedded. The material imbedded in the primary fibres is 

 very various, principally grains of sand, but frequently also fragments 

 of spicula disposed at various angles to the axial line of the fibre. 

 At first sight it would almost seem as if a discretion were exerted iu 

 the choice of the grains of extraneous matter imbedded; they are 

 selected of such uniform size, and are disposed in the fibre with so 

 much regularity. This is effected in the same manner as that de- 



