240 Proceedings of the Royal Society of Victoria. 



suggested* that Halichondria may be derived from a Stellettitiopsis- 

 like ancestor by loss of the asters, and the chai-acters of the 

 present species certainly seem to strengthen this supposition. 



^.^V: 450 (s. 9, 17 f., "blackish slate"); 685 (s. 9); 727 (s. 5). 



B.M. d. 102 {'■'■ A/iiorf/iina nigj'ocietis" unregistered). 



Genus Eu mas tin, Schmidt, f 



Sponge consisting of a massive body bearing elongated mammi- 

 form projections with vents at their apices. Skeleton consisting 

 of long slender oxea, arranged irregularly or in loose fibres. 



The genus resembles Oceanapia in external appearance, but 

 differs in the large slender oxea, and probably also in the absence 

 of the bast-like subderraal skeleton reticulation. 



Euniastia schinidtii, n. sp. 



The sponge consists of a hemispherical body, with long and 

 short finger-like processes springing from its upper surface. 

 Numerous minute vents occur at tlie summits of the larger 

 fistuUe. 



Skeleton, composed of thickly, but irregularly scattered oxea, 

 sometimes collected into loose wliisps and slightly projecting 

 from the surface in loose tufts. 



Spicules, long slender oxea,, slightly curved and gradually 

 sharp-pointed at each end ; closely resembling those of a typical 

 Halichondria ; measuring about 0*4 by 0"008 mm. 



J?.N. 390. 



Sub-family Chalinin.e. 



A considerable amount of spongin is present, typically ft)rming 

 a thick sheath completely enveloping the sjjicules and uniting 

 them into strong fibres. (In many species the spicules become 

 greatly reduced in size and numbers, while the horny matter 

 increases, thus forming a gradual transition to the so-called 

 Horny sponges). 



Genus Pachychalina, Sc-hmidt. 

 External form various, but not tubular. Fibres stout, with 

 spicules numerous and arranged polyserially. 



» Challenger Tetraotinellida, p. 208. 



tGnmdzUge einer Spougien-Faiinii des atlantisdien Gcbietcs,)). 42. 



