﻿SPONGES.-HALLMANN. 



271 



This species has been written by Dendyi as a possible 

 synonym of O. subhispida — though there is little in the des- 

 criptions of the two that would suggest 

 an identity. However, in the Austra- 

 lian Museum collection of Port Phillip 

 sponges there are five specimens, in j) 



external appearance much resembling // 



a Chalina, which — if allowance be made ,. 



for certain differences attributable to -' 



differences in condition of preservation (j 



— agree so well with the description of 

 Axinella chalinoides, var. cribrosa, that 

 I feel no hesitation in identifying them 

 as such. These also agree equally well 

 with the typical A. chalinoides, save 

 that, concerning the latter, auxiliary 

 megascleres have not been mentioned ; 

 but these spicules might easily be over- 

 looked, and I therefore regard it as 

 extremely probable that A. chalinoides 

 and its so-called variety are the same. 



One of the five specimens, which is 

 dry and dermally denuded, has com- 

 pressed dichotomous branches and 

 many marginally-situated shallow 

 crateriform oscula, each of w^hich forms 

 the common orifice of several (usuallv 

 three or four) excurrent canals opening 

 into its base. In the remaining speci- 

 mens, preserved in alcohol, the 

 branches are either cylindrical or com- 

 pressed and, owing to rapidly repeated 

 dichotomy, sometimes appear to divide 

 polytomously ; and the oscula which 



are not entirely confined to opposite sides of the branches, 

 are more or less concealed from view by a covering membrane 

 or diaphragm, continuous with the thin though well-defined 

 dermal membrane. The oscula diaphragms may be (ap- 

 parently) entire, or may have a small central circular aperture ; 

 sometimes, owing probably to collapse, they are depressed 

 below the general surface, and are then in a few cases radially 

 wrinkled. Immediately beneath the thin transparent dermal 

 membrane are numerous subdermal spaces or lacunae, which 

 can be seen to lead by rather large circular pores into the in- 

 current canals. To these lacunae and pores is due, probably, a 



Fig. 59— a c/tal- 

 inoides. a Princi- 

 pal stylus, b Aux- 

 iliary stylus. 



1 Dendy— Proc. Koy. Soc. Vict., viii. (n.s.), 1896, p. 36. 



