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THE VOYAGE OF H.M.S. CHALLENGER. 
spines behind. A prominent rostral pouch, supporting a small avicularium on the front 
of the zocecium below the orifice. Ocecia very prominent, globose, rather wider than 
high ; surface granular with a faintly marked, beaded border. 
Habitat. — Marion Island, 50 to 75 fathoms (on Fucus ). Station 167, lat. 39° 32' S., 
long. 171° 48' E., 150 fathoms, blue mud. 
The oral spines remain, apparently, only on the youngest zooecia at the growing edge 
of the colony. 
(9) Schizoporella cecilii, Audouin (sp.). 
Flustra cecilii, Aud., Expl. i. p. 239 ; Savigny, Egypte, pi. viii. fig. 3. 
Lepralia cecilii, Bk., Quart. Journ. Micr. Soc., vol. v. p. 173, pi. xv. figs. 6, 7 ; Macgillivray. 
Schizoporella cecilii, Hincks, Brit. Mar. Polyz., p. 269. 
Habitat. — Station 161, off Port Philip, 33 fathoms, sand. 
(10) Schizoporella circinata, Macgillivray (sp.). 
Lepralia circinata, Macgilliv., Nat. Hist. Viet. Dec. iv., p. 21, pi. xxxv. fig. 1. 
Character. — Zoarium adnate (on coral). Zooecia broad, ovate, convex in front, no 
interzocecial septa. Surface in the middle prominent, quite smooth, outside of which 
it is widely punctate or pitted. Oral orifice semicircular, 
with a perfectly straight lower border with a median narrow 
notch or fissure which widens out below and lodges a 
moveable process connected with the operculum ; 6 to 8 
long articulated oral spines above. Ooecium lofty, pro- 
minent, glassy, smooth. Sometimes a long channel-like 
retentive avicularium on the front, the mandible pointing 
downwards. 
Habitat. — Station 135a, off Inaccessible Island, Tristan 
da Cunha, 75 to 90 fathoms, hard ground, shells, gravel. 
The very peculiar conformation of the operculum in 
this species, exactly resembling that of Schizoporella cecilii 
in miniature, affords at once a distinctive character, as I 
am unacquainted with any other form with a similar kind 
of operculum. What is the nature of the curious little 
moveable appendage jointed to the operculum, in this and 
the preceding species, is by no means clear ; but it would seem that a minute fasciculus 
of muscular fibres is connected with its lower part. The accompanying woodcut shows the 
characters above described, as well as the great difference in size of the operculum (a) of 
Schizoporella cecilii. 
Fig. 46 . — Schizoporella circinata. 
a., Operculum of Schizoporella cecilii. 
