70 RECORDS OF THE AUSTRALIAN MUSEUM. 



The margins of the lamella? are split into numerous large or small 

 fronds, these again producing other compressed lobes. The thick- 

 ness of the lamellae rarely exceeds 7 or 8 mm. The surface exhibits 

 many wavy lines of growth ; the texture is fine, close, elastic, and 

 very tough ; the colour is dark amber-brown. The oscula are 

 generally confined to the inner aspect of the lamellae ; their diameter 

 is between 1 and 2 mm. ; the margins are thin and somewhat 

 elevated, the walls being supported by pillars of fibre between 

 which occur several circular apertures. The spicules consist of 

 slightly curved oxea from 007 to 009 mm. in length, and about 

 0005 in diameter. 



In habit this species is extremely variable, ranging from bunches 

 of lingulate branches to flabellate or half cup-shaped. 



A Museum specimen, labelled Plachoclialina pedunculata, var. 

 dura, Lendenfeld (No. 230), is identical with the above. 



A single plate-shaped specimen, from the Hawkesbury River, 

 resembles Euplacella australis, Lendenfeld, yet the spicular charac- 

 ters are the same. The example arises from a central peduncle, 

 60 mm. in length. The circular plate-like lamina is over 300 mm, 

 in diameter, and from 3 to 5 mm in thickness. The sponge 

 exhibits five or six longitudinal folds ; the outer surface presents 

 numerous concentric ridges or growth lines ; these lines are also 

 visible -on the outer half of the upper surface; the latter is closely 

 sprinkled with oscula, about 1 mm. or less in diameter, and from 

 1 to 2 mm. apart. The spicules are curved oxea, gradually sharp 

 pointed. Size— 007 to 00-8, by 0004 to O-OOa mm. 



From Tuggerah Beach. 



Pachychalina communis, Lendenfeld, sp. 



Chalinissa communis, Lendenfeld, Zool. Jahrb., ii., 1887, p. 772; 

 id., Aus. Mus. Cat., xiii.. Sponges, 1888, p, 87, pi. vii. 



This species is very common in Port Jackson, and also along 

 the coast. It exhibits great variation in habit, ranging from 

 flabellate to digitate. In the quiet waters of Port Jackson, the 

 sponge usually consists of a flabellate or folded lamella, or it may 

 be composed of a bunch of flattened branches, which are connected 

 at the base, forming broad lamella? here and there, as represented 

 by the figured type. In the rougher waters of the coast, large 

 subflabellate examples are absent. The habit is digitate, with 

 narrow angular or subcylindrical branches. It appears highly 

 probable that P. communis, with its varieties Jiabellum and 

 digitata, Lendenfeld ; P. macropora, Lendenfeld ; P. elegans, 

 Lendenfeld ; P. elongala, Lendenfeld ; and P. tenuijibris, Len- 

 denfeld ; are all close allied forms, differing in habit and density 

 according to the habitat in which they have grown. The number 

 of intermediate stages between them are endless, and a well grown 



