sponges from Funafuti. '.\r)0 



Poli/Jibrospongui Sweet i\ sp. n. (PI. XV. Hg. 2, a-r.) 



Sponge forming an irregular incruafing mass, 4 centiin. in 

 length, 2'0 contim. in width, and 1 cciitim. in thickness, 

 nearly encircling the stem of a Cor/jonm; with long mem- 

 branous yellow oscular tubes about 2 ccntim. in height, 

 occasionally branched. Dermal membrane smooth, perga- 

 mentacoous, yellowish white. 



Skeleton. — Ectosomal : composed of stout primary fibres 

 30 to 60 /i in thickness, partly cored with foreign bodies, 

 the meshes being filh'd in by thinner clear fibres and crowded 

 with foreign bodies ; the oscular tubes consisting of a con- 

 tinuation of the dermal layer, but with the cored fibres forming 

 a regular network with square meshes. 



Choanosomal skeleton composed of an oval-meshed network 

 of loose bundles of slightly branched anastomosing fibrils, the 

 diameter of the bundles being 210 fi and of the fibrils 9 /x ; 

 also of sparsely scattered slightly branched fibres 50 fj, thick, 

 and passing from the base to the surface, composed of foreign 

 bodies cemented by spongin. 



Filaments absent. 



This remarkable species is nearly related to Polyfibro. 

 upongia JJaheUiftra, Boworbank, a thin flabellate species from 

 New Guinea, but differs in shape and in liaving the oscular 

 tubes. The type specimen of Bowerbank's species is in the 

 Dresden Museum, but the Bowerbank collection contains two 

 filides prepared from the type, and quite sufficient to show the 

 close similarity in the skeletal structure of the two species. 



Lendenfeld puts Bowerbank's species in a subgenus Poly- 

 fihrospongia under the genus Hircinxa. After a careful search 

 I have been unable to find filaments in either of the above 

 two species, though these mysterious objecrs are abundant in 

 a specimen from Port Jackson named by Lendenfeld Hircinia 

 ( Po lyjih rospo ng ia ) gigo. n tea . 



To include //. gigante.a in the same genus with Polyfibro- 

 spongia Sweetii\x\(\jiahelhfera\\o\x\*\ be tantamount to regarding 

 the filaments as Unessential elements from the systematic point 

 of view. I have not at jiresenta definite opinion on this difficult 

 controversial question of the systematic value of the filaments, 

 a question on which equally eminent spongologists take 

 diametrically opposite views. 



For the present I shall retain Bowerbank's genus with 

 the two 8|)ecies Sweeti and flabelUfera, placing it next to 

 Stclospongus, and shall leave //. gigantei and fascicuJata 

 under Hircinia. The new species is named after Mr. G. 

 Sweet, whose munificent donations rendered possible the 

 success of the Australian Boring Expedition. 



Locality. \V. of 'J'utanga, 86 fath., Funafuti Atoll. 



