MEYENIA. — EENIERA. 



77 



The sponge grows on immersed branches, which it encloses sometimes entirely 

 for a length of 50 millim., and attains a thickness of 30 millim. ; it is toler- 

 ably hard. The skeleton consists of spicule-bundles. The canals are remark- 

 ably wide, and the sponge therefore appears very lacunose. 



The gemmules are situated at the base; they coincide entirely with those of 

 the European forms, which I have been able to compare with this Australian 

 variety ; their average diameter is 0-35 millim. The skeleton-spicules are not 

 so spindle-shaped as those of other forms of the same species, but appear more 

 cylindrical and abruptly pointed ; they are on an average 0-22 millim. long 

 and 0-01 millim. thick in the centre and slightly spiny ; the spines are on an 

 average 0*008 millim. high and 0-01 millim. apart ; there are no larger thorns. 

 I have never seen any perfectly smooth spicules. The amphidiscs of the 

 gemmule-capsules are 0-029 millim. long, and possess a very stout shaft which 

 is 0-005 millim. thick. On this shaft there are a few stout spines, the 

 length of which is about two-thirds of the thickness of the shaft. 



This variety is distinguished from the preparations of Bowerbank and Carter, 

 which I have examined in the British Museum, by the considerably larger size 

 of the supporting-spicules, and also by the amphidiscs of the Australian 

 variety having large and stout thorns, which is not the case in those of the 

 European form. Cylindrical skeleton-spicules, which, according to Carter, do 

 not occur in the European form, are nevertheless to be found in some of 

 Bowerbank's type-preparations. The terminal discs are 0-02 millim. broad 

 and very strong; their margin is deeply serrated. The teeth are about 12-16 

 in number. 



Geographical Disteibtjtion.— Bell Eiver, Wellington, New South "Wales 

 (Haswell). Macquarie Eiver, near Dubbo, New South Wales (Lendenfeld). 



Familia HOMORRHAPHID^. 



Cornacuspongise with oxeote or strongylote megasclera ; no dif- 

 ferentiated microsclera, except toxea. Without gemmulse. Marine. 



Subfamilia RENIERINiE. 

 Spicules never completely enveloped in horny fibre. 



Genus RENIERA. 

 Homorrhaphidse with a skeleton composed of loose spicules, 

 which form a network with triangular meshes. 



The spicules for the most part do not form bundles, but remain isolated and 



