TETRAXONIDA. 29 



Several oscules about 'J mm. iu 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 ;u,; acanthostyles spined at the head and near the point, 447 x 16 /x ; 

 larger anisocheles 36 /x long, a smaller kind 20 ^t long; bipocilla 9' 75 ,« long, usually 

 with one end pocillate and the other flattened and with three to five 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 ^c reaching from surface to 

 centre, and with anisocheles with a spine at the small end, 15*9 m long and arranged 

 in rosettes, the latter being distributed around the summ^it of the spicular plug or 

 (•ylinder. 



Specimens were obtained from (l) 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 Inland, 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 SPATULATrS. 



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

 r,)()7. lophon spatulattes Kirkpatrick (10a. p. 27(;). 



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 2S fx. 



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 oljliquely or transversely by fibres one or two spicules thick, which 

 support the dermal membrane. 



Spicules. IMegascleres, smooth styles, 462 x 25 fi, with a mucro at the basal end. 

 Ectosomal sub-amphityles 225 x 12-5/x,, 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 /a long, G • 2 /a broad (front view). 



Bipocilla, rare, 13'6/u, long, 1-15/x 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 



