TBTRAXONIDA. 29 



Several oscules about 9 mm. in diameter occur along the margin ; they are slightly 

 raised and with a thin plain rim with special spicular armature. The pores occupy 

 irregular oval areas about 2 mm. in diameter. The spicules resemble those of 

 specimen No. 421 described by Topsent, the dimensions being as follows : — The amphi- 

 tyles 266 x 10 /a ; acanthostyles spined at the head and near the point, 447 X 16 /x ; 

 larger anisocheles 36 /j, long, a smaller kind 20 ,« long ; bipocilla 9 • 75 /x long, usually 

 with one end pocillate and th-e other flattened and with three to fi.ve minute denticles. 



An interesting feature is the presence of embryos "25 mm. in diameter with a 

 solid cylindrical core of peculiar spined amphityles 105 X 5 fi reaching from surface to 

 centre, and with anisocheles with a spine at the small- end, 15"9 /x long and arranged 

 in rosettes, the latter being distributed around the summit of the spicular plug or 

 cylinder. 



Specimens were obtained from (1) Winter Quarters No. 12 hole, 25-30 fms. ; 

 (2) East end of Barrier, 100 fms. ; (3) No. 5, Seal Hole, 178 fms. ; (4) From near the 

 ship, February 28, 1902 ; (5) Off Coulman Island, 100 fms. 



The 'Belgica' collected specimens from Lat. 71° 14' S., Long. 89° 14' W., 

 450 metres, and from Lat. 71° 19' S., Long. 87° 37' S., 450 metres. 



lOPHON SPATULATDS. 



(Plate XXL, figs. 5, 5a"-c, and Plate XXV., fig. 5a-d.) 

 1907. lophon spatulatus Kirkpatrick (10a. p. 276). 



Sponge slender, cylindrical, branched. Colour, pale brown in spirit. Oscules 

 oval, about 1 x • 6 mm. in diameter, slightly raised ; surrounded by a radiating zone of 

 tyles. Pores in sieve-like areas 2-3 mm. in length and about 2 mm. in breadth, on 

 a level with the general surface. 



Flagellated chambers 26 X 23 /*. 



Skeleton; Dermal ; a closely packed layer of dermal amphityles. 



Choanosomal, a loose network of 3-6 spicules thick, forming the core of the 

 cylinder; multispicular fibres, giving off strands at right angles; the longitudinal 

 fibres are joined obliquely or transversely by fibres one or two spicules thick, which 

 support the dermal membrane. 



Spicules. Megascleres, smooth styles, 462 x 25 jn, with a mucro at the basal end. 

 Ectosomal sub-amphityles 225 X 12-5 ju,, fusiform with the swelled ends smooth 

 laterally, and with the extremities only slightly convex, in fact almost truncate, and 

 covered with spines. 



Microscleres. Palmate anisochelse 18 • 7 /u, long, 6 ■ 2 /x broad (front view). 



Bipocilla, rare, 13-6/1, long, I'IS/a thick, shaft deeply curved, slightly twisted, 

 and with ends almost similar, spatulate, with crenulated edges ; occasionally with five 

 relatively large denticles in place of the finer crenulation. A second kind of 

 bipocilla have a longer, less curved shaft with scoop-like rather than spathulate 



