﻿SPONGES.-HALLMANN. 22 ■? 



Microscleres. — 



(i.) Scarce isochelae palmatte, 8-12 }i long. 



(ii.) Long- slender toxa, tolerably plentiful, of character- 

 istic though somewhat variable shape, 160-260 // in 

 length and, at most, 1.5 /.' in diameter. 



Loc. — Port Jackson (Austr. Mus. Coll.). 



Clathria partita, sp. rwv. 

 (Plate xxxii., fig. 3; and fig. 46.) 



Sponoe stipitatc, u<ith few, broad, niiicli compressed, 

 free or coaJesceui brdiu-hes spread faii-iVise in one plane. 

 Branches transversely furrowed. The dry sponge is 

 covered with a whitish incrustation of dermal spicules, 

 ■beneath which the surface is dotted, with pinhole-like 

 ''pores.'',' Main skeleton a very irregidar reticulation of 

 horny fibres with loosely {and, in the comiecting fibres, 

 usually uni- or bi-serially) arranged spicidcs. hnvardly 

 the fibres are fairly stout, but superficially they become 

 slender and paucispicidar, and form a iveb-like meshwork 

 in which main and connecting fibres are not distinguish- 

 able. Ecliinating spicules scarce, comprising both acces- 

 sory and principal styli, as well as occasional intermediate 

 forms. Megascleres : (i) Principal styli, smooth, slightly 

 curved, 240 x 9 p; {ii.) acantho styles, seldom more than 

 85 X 6 11; {Hi.) auxiliary styli, smooth, straight, J50 x 

 4.^ p. Microscleres : Hair-like toxa about 200 ji long. 



The single specimen is a tall flabellate sponge with an 

 •elongated cylindrical stalk and a small number of dichotomous 

 much compressed, strap-shaped branches ; in shape it bears 

 some resemblance to a deeply incised palmatipartite leaf. The 

 branches usually increase slightly in breadth upwards, thus 

 becoming spathulate ; lateral union between them sometimes 

 occurs, and it is possible that in some instances the separated 

 branches may be represented or replaced by a continuous 

 lamina. The specimen measures 400mm. in total height; the 

 thickness of the branches at right angles to the plane of 

 branching is about 6 mm. The surface is ornamented with 

 shallow furrows and narrow intervening ridges, running, as a 

 rule, transversely to the margins of the branches. They are 

 ■never a very conspicuous feature and are sometimes obscure. 

 Thev are most clearlv defined towards the lateral borders of 



