Sponges from South Australia. 447 



There is also another fragment of a large cylindrical tube 

 similarly truncated (probably by the dredge), but of a very 

 different kind, inasmuch as this consists of a portion of a large 

 tube which is divided into several finger-like small ones, in 

 which also the spiculation is so different that there can be no 

 hesitation in at once making it the type of a new species, if 

 not genus, in this family ; hence it will be described and 

 illustrated under tlie folio wing: name : — 



Phlceodictyon hirotuUferum^ n. sp. (Pi. X. figs. 1-5.) 



Fragment consisting of a stiff, hollow, cylindrical tube with 

 thin wall, about 2\ in. in diameter and the same in length, 

 which afterwards divides into three branches, one of which, 

 about 2 in. long, remains single, but with a bud upon its 

 middle (PI. X. fig. 1, and c), while the other two become united 

 about their middle, and then divide into four, which vary a 

 little under 2^ in. from the first division ; branches tubular, 

 cylindrical, slightly diminishing towards the free ends, which 

 are round and closed. Tubulation resilient, open, chiefly 

 on account of the structural arrangement, of which here- 

 after. Colour grey. Surface smooth, especially over the 

 main or lower portion (fig. 1, a) and for more than two thirds 

 of the branches, the rest poriferous (fig. 1,,/). Pores in the 

 dermal structure covering the last third of the branches 

 respectively. Vents not seen. Structure of the main portion 

 of the tubulation (fig. 1, a) consisting of three coats, of 

 which the external is composed of a layer of small cells in 

 juxtaposition, about 2-6000ths in. in diameter, but being 

 mixed with those of Melohesia and Polyzoa, which have 

 overgrown this part, I am unable to say whether they are or 

 are not all epithelial : the middle, a layer of skeletal spicules 

 arranged parallel and close to each other, transversely to the 

 direction of the tube ; and an internal layer consisting of soft 

 fleshy sarco-fibre, so voluminous and loose that a portion 

 (fig. 1,0?) hangs outside the basal end of the tube. As the 

 main portion of the tubulation approaches the last third of the 

 branches the sarco-fibrous or internal structure, whicli is of 

 considerable thickness, gradually assumes a reticulated or 

 clathrous character, in which the holes, which are more or less 

 circular, infundibuliform, and fenestral in appearance, open 

 externally in the way that will be presently mentioned. 

 During this transition the spicules of the spiculiferous layer 

 gradually lose their transverse arrangement and become 

 bundled into a skeletal structure, which is fibro- reticulated 

 longitudinally, that is the meshes are elongated in this direc- 



