SPONGES — WHITELEGGE. 461 



at least half their length through the dermal membrane. The 

 primary fibres are about O'Ol to 0-15 mm. in diameter and 0-5 mm. 

 apart ; the spicular core consists of a thin undulating line of 

 ill-arranged oxea; these are either multiserial, or, in the slender 

 parts, five or six in a row. The transverse connecting fibres are 

 given off at pretty regular intervals ; they are 0*04 to 005 mm. in 

 diameter and about "6 mm. apart. The spicules are uniserial, 

 and frequently separated by a space equal to their length ; there 

 are about four spicules in each fibre. The mesh of the fine dermal 

 network is very irregular, and the inhalent pores are from 0*1 to 

 015 mm. in diameter. 



The spicules are sharp-pointed oxea 0-035 to 0-04 by 0-0015 to 

 0002 mm. 



The specimen described has been identified by comparison with 

 a fragment from the Lendenfeldian collection now in the British 

 Museum. The example referred to was labelled " Ceraochalina 

 Zevi's, Lendenfeld, Torres Straits." Both the "Thetis "and the 

 British Museum specimens agree with the description and figure. 



There is, however, a second fragment received from the British 

 Museum, which, although labelled Ceraochalina levis, Lendenfeld, 

 appears to be quite distinct, and apparently has no resemblance 

 or character by which it could be associated with C. levis, Ldf., 

 except that they both possess oxeote spicules, but very different 

 in dimensions. The sponge in question appears to be the one 

 referred to in Lendenfeld's description of C. levis as an "algal 

 pseudomorph " from Port Chalmers, New Zealand. I have 

 examined many specimens of this form, in which an alga and a 

 sponge are thoroughly united ; there are numerous examples in 

 the Australian Museum from "West Australia, New Caledonia,. 

 New Hebrides, and Torres Straits. From the data at my dis- 

 posal I am inclined to the opinion that the true C. levis, Ldf., is 

 from Port Chalmers, and that the "algal pseudomorph" is from 

 Torres Straits ; at least, it appears so from the distribution of the 

 algal form as given above ; all the well-authenticated specimens 

 come from coral regions. 



The following is a description of the algal pseudomorph drawn 

 from well-preserved spirit and alsodried specimens: — Pseudomorph 

 usually consisting of a series of more or less interlaced, decumbent, 

 and often coalesced branches, which vary from lamellate to 

 cylindric ; the latter are usually about 10 mm. in diameter. The 

 surface is smooth, porous, and exhibits numerous scattered oscula 

 from 1 to 1-5 mm. in diameter. Jn section the algal portion 

 presents an irregular reticulation of filaments. I failed to find 

 any indication of spongin or fibres, but the spicules form a loose 

 and ill-arranged sheath around the delicate branches of the alga. 

 Here and there a few spicules occur in the mesh of the network^ 



