1G4 
THE VOYAGE OF H.M.S. CHALLENGEE. 
stands behind and free of the zooecial orifice. Two or sometimes four of the marginal 
spines persist in front of the ocecium. On the dorsal aspect the zooecia are irregularly 
hexagonal and convex, with a small circular pore in the centre of each. Zooecia about 
0"'02 wide ; orifice 0"'005. 
Habitat. — Station 312, lat. 53° 37' S., long. 70° 56' W., 10 to 15 fathoms, blue mud. 
The chief peculiarities of this form are : — 1. The great length of the oral spines on the 
young zooecia and the curious structure presented by some of them, which are more or less 
compressed, whilst the majority are cylindrical or terete ; both appear to be indistinctly 
jointed, and many, instead of a single long and acute point, have a small terminal joint 
supporting two minute conical points. 2. Besides the central pore on the dorsal wall, 
many of the zooecia present hollow conical elevations, by which, as it would seem, the 
very scanty calcareous adhesions are formed. 
(4) Schizoporella auriculata (?), Hassall, var. alba, nov. (PI. XIX. fig. 1). 
Character. — Zoarium delicate, thin, white ; zooecia rhomboid or subovate, deeply 
immersed, no septa ; disposed in lines radiating from the centre. Surface vitreous, 
granular, very obscurely punctured round the border. Orifice orbicular, emarginate, with 
four superior marginal spines. A prominent conical rostrum immediately below the 
orifice, with a circular avicularium on the summit. Ooecia about half immersed, lofty, 
convex in the front which presents a circular circumscribed area including numerous 
punctures of unequal size and more or less angular in shape. 
Habitat. — Station 135c, off Nightingale Island, 110 to 150 fathoms, and (135a) off 
Inaccessible Island, Tristan da Cunha, 75 to 90 fathoms, hard ground, shells, gravel. 
Probably closely allied to Schizoporella auriculata, but differing in the absence of any 
raised septal line between the zooecia, and it may be added in the white colour, and more 
particularly also in the shape of the operculum. 
(5) Schizoporella jacksoniensis, n. sp. (PL XIX. fig. 3). 
Character. — Zoarium rather thick. Zooecia broadly ovate, very convex, with a 
distinct raised line round the border. Surface reticulato-punctate. Orifice emarginate, 
peristome thickened, smooth, slightly raised above (not in front). A rather large sessile 
avicularium on one side of many of the zooecia with an acute triangular mandible, 
directed upwards, Ooecia inapparent. 
Habitat. — Station 163b, off Port Jackson, 35 fathoms, hard ground (parasitic round 
a Sertularian). 
