24 THE VOYAGE OF H.M.S. CHALLENGER. 



deal of spongin ; fibre about 0'07 mm. thick, polyspiculous, spicules not confined to tlie 

 centre of tlae fibre. 



Sjncules. — Slightly curved oxea, fairly sharply and gradually pointed ; size about 

 0-1 mm. by 0-0065 mm. 



ioca%.— Station 162, April 2, 1874; lat. 39° 10' 30" S., long. 146° 37' 0" E. ; 

 Bass Strait ; depth, 38 fathoms ; bottom, sand and shells. One specimen. 



Pachychalina (?) punctata, Eidley and Dendy (PL VI. figs. 2, 2a, 2h, 2c; PI. XLVI. 

 figs. 1, 2). 



1886. Paehijchalina (?) punctata, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. .5, vol. 



xviii. p. 329. 



Sponge (PI. VI. fig. 2) erect, flattened, lobose. The single specimen in the collection 

 •consists of a large flattened lobe, bearing near the summit two smaller ones. The large 

 lobe may itself have been formed by the coalescence of smaller ones, as there are two 

 large holes right through it. Height of sponge 143 mm. ; breadth 87 mm. ; thickness 

 about 6 mm. Colour in spirit rather dark greyish-yellow. Texture very tough and 

 leathery, compressible and elastic. Surface very uneven but glabrous. Oscula (PI. VI. 

 figs. 2, 26, o), small round openings, scattered at about equal distances from one another 

 on one side only of the sponge; diameter about 1 mm. Pores (J) (PI. VI. figs. 2, 2a, 

 2b, p, 2c, p, and PI. XLVI. fig. 1) unusually large ; visible to the naked eye as minute 

 openings scattered singly but very abundantly on both sides of the sponge (PL VI. figs. 

 2, 2a) ; diameter up to about 0-35 mm., but varying, and usually smaller. They appear 

 to be lined by spongin (?), which projects into their cavities in large bosses, frequently 

 arranged so that the cavity has the form of a cross, the four angles between the arms being 

 filled up by four projections of spongin (?) (PL XLVI. fig. 1). Possibly this arrangement 

 is to guard against the ingress of noxious parasites, &e.^ 



Skeleton. — (a) Dermal ; a very well-developed, close-meshed reticulation of spiculo- 

 fibre (PL XLVI. fig. 1), with plenty of spongin, and echinated abundantly by projecting 

 sjaicules. Meshes only about 0-07 mm. wide, (b) Main; also very well developed, with 

 strong primary fibres, about 0-07 mm. thick, radiating to the surface, and crossed by 

 secondary fibres in a lattice-like manner (PL XLVI. fig. 2). Fibres polyspiculous, but 

 with a thick sheath of spongin. Also numerous scattered spicules between the fibres. 



Spicules. — Slightly curved, sharply and rather gradually pointed oxea; size aliout 

 009 by 0-0055 mm. 



The species is very weU characterised, the most characteristic and interesting point 

 being the special means adopted for guarding the inhalent apertures (if such they be). The 

 amount of spongin present in the sponge is very large, whence its tough and leathery 



1 Probably pores also occur as small openings through the thin dermal membrane, but we are not certain about 

 this point. 



