148 On Sponges from South. Australia. 



P.S. — Since the above was written, T have found a much 

 larger and more typical specimen of Lelapia australis, Gray 

 (to which I have given particular prominence on account of 

 its connexion with fossil species), which by accident had been 

 overlooked in one of Mr. Wilson's later collections from " Port 

 Phillip Heads," and therefore take this opportunity of ap- 

 pending a description of it as follows : — 



Lelapia australis, Gray. 



Cylindrical, clavate, the largest part upwards, somewhat 

 curved or bent upon itself, rugose longitudinally. Consis- 

 tence firm. Colour dark grey. Surface even, smooth, inter- 

 rupted by the projection of crooked ridges extending from the 

 free to the fixed end, subspirally and longitudinally, in broken 

 lengths, sometimes reduced to mere scattered tubercular points, 

 most pronounced on the concave side towards the month, 

 least so on the opposite side ; largest and most continuous 

 ridge l-3rd in. long, l-48th in. broad, and 3-48ths in. high. 

 Pores plentifully scattered over the surface, not remarkably 

 large. Vent single, terminal, represented by a narrow, ellipti- 

 cal opening about l-3rd in. in its longest diameter, so constricted 

 in the centre as to be closely approximated by an infolding of 

 the lip on each side ; provided with a peristome whose spicules 

 here are broken off short; leading into a cloaca corresponding 

 in shape with the specimen, that is wide above, narrowed to 

 a point below (after which the stem becomes solid) ; in other 

 respects the same as that above described. Structure of the 

 wall, which is about 5-24ths in. thick, together with the spicu- 

 lation, also much the same as above described ; but with 

 these exceptions, viz. that the large acerate spicule of the 

 " body " appears to traverse the wall horizontally as well 

 as longitudinally ; while the " ridges " are composed of a 

 mass of acerate spicules of different lengths and thick- 

 nesses, averaging 150 by 2|-6000ths in., some of which are 

 simply pointed at each end, others bent and lance-shaped 

 at one end and simply pointed at the other, and a third 

 bent and lance-shaped at each end ; all in contact longi- 

 tudinally with each other, forming a wedge-shaped mass 

 whose narrow end or border, according to the length of the 

 ridge (that is whether linear or reduced to a small tubercular 

 point), is slightly sunk into the wall, and the other, whose 

 spicules, like those of the peristome here, are broken off short, 

 spread out into the ridges of the surface, where the cuticular 

 layer of " mortar-spicules " banks it up on each side. In a 

 dried fragment these masses, in the section especially, present 

 the glistening white aspect of the peristome. Size of specimen 



