COLLECTED BY THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 431 



Order TETRAXONIDA. 



Grade Tetractinellida. 



Sub-order ASTROPHORA. 



Family Geodiid^;. 



Geodia littoralis n. sp. (Plate XXXVIII, fig. 5 ; Plate XL, fig. 1.) 



Station 482. Houtjes Bay, Saldanha Bay, shore. 19th May 1904. Three 

 specimens. 



Sponge more or less rounded in outline, but very irregular. Two of the 

 specimens are complete, except that in places their surface is injured. Each has 

 a thick, finger-like projection from one end. 



The specimens grew apparently quite free, as there is no sign that they were 

 attached at any point. The largest measures 13 '5 cm. by about 8 '5 cm., and is 

 about 4 '5 cm. thick. Another is 10 '2 cm. in length by 10 cm., and is about 5 cm. 

 thick. The third specimen is broken. It is 6 '5 cm. in its greater diameter. 



The surface is strongly hispid in places. 



The colour in spirit is pale yellow throughout the whole sponge. 



The excurrent chones occur in groups, generally in slightly depressed areas ; 

 they are similar to the incurrent chones, except for their greater size. Both 

 excurrent and incurrent openings are covered by a cribriporal membrane, which is 

 echinated by tufts of cortical oxea and anatriaenes. The excurrent openings are 

 about 0'125-0'175 mm. in diameter, the incurrent being about 0'025-0'06 mm. 



The main skeleton consists of radiating bundles of megascleres. The cladi of the 

 orthotrisenes are extended beneath the sterrastral layer, which is about 1"2 mm. in 

 thickness, but many of the anatrisenes and mesoprotrisenes pierce the layer of 

 sterrasters and project for some distance beyond the surface of the sponge. 



Vertical bundles of small oxea occur in the cortex, and among them are minute 

 anatrisenes. These project slightly and cause the finer hispidation of the surface. 



Spicules. — (l) Orthotrisenes. — The shaft tapers gradually to the rounded 

 proximal end. It is about 2'5-3 mm. in length by 0'065-0'09 mm. Cladi 0'25- 

 0'4 mm. in length. (2) Anatriaenes. — Shaft rounded at the proximal end, 4'5-5 mm. 

 long by '025-0 '03 mm. beneath the cladome. Cladi 0'1-0'14 mm. long. Cladome 

 about 0'1-0'14 mm. (3) Cortical anatriaenes. — Not very common. Length 0'26- 

 0'35 mm. by 0'005 mm. Cladi to about 0'008 mm. in length. (4) Mesoprotrisenes. — 

 Shaft generally rounded at the proximal end and produced at the distal end to a 

 length of 0'075-0'13 mm. above the origin of the cladi. Shaft up to about 4'5 mm. 

 in length by '025-0 '035 mm. Cladi 0'05-0'l mm. long. (5) Somal oxea. — These 

 taper gradually to rather blunt points. Sometimes one end is rounded off. Length 

 2'5-3 mm. by 0'05 mm. (6) Cortical oxea. — These taper to rather blunt points. 



TRANS. ROY. SOC. EDIN., VOL. L, PART II (NO. 15). * 61 



