REPORT ON THE POLYZOA. 
177 
small median sub orbicular immersed, oral avicularium. Ooecia flattened in front with 
a depressed circular cribriform area. 
Habitat. — Simon’s Bay, Cape of Good Hope (on a Membranipora). 
A second lepralian species of the genus, constituted as above, is the Gemellipora 
striatula, Smitt ( loc . cit., pi. xi. fig. 207), in which there is apparently a small median 
avicularium ? above instead of below the orifice. 
Family XXI. Adeone.e, n. fam. 
Escharidce (pars), Auctt. 
Character . — Zoarium erect or (rarely) encrusting, affixed either by a more or less flexible 
jointed or unjointed, radicate, chitino-calcareous peduncle, or immediately attached to 
some flexible body, either with or without a contracted base. Bilaminar except when 
encrusting; foliaceous, expanded and fenestrate; or branched or lobate and entire. 
Cells of two or usually three kinds, zooecial, ocecial, avicularian. No ooecia of the usual 
type. On the front a median pore, usually simple and circular, sometimes irregularly 
fimbriate, or represented by a depressed perforated areola. Usually one or more sessile 
avicularia on the front. In the ooecial cells the pore in most cases is suboral, or placed 
immediately below the mouth, and usually a minute avicularium on each side. The 
wall of the zooecial cells is punctate or entire, that of the ooecial always punctate. 
The forms included in the group above indicated appear to constitute a natural and 
well marked assemblage, distinguished, notwithstanding a considerable diversity of habit, 
by very peculiar characters. Amongst these may be briefly noticed : 
1. The existence of three distinct forms of cells. 
2. The entire absence of ooecia of the usual type, whose function appears to be 
discharged by special cells, usually marginal but sometimes interspersed amongst the 
others, from which they differ in size and form, as well as in other more important 
respects. They are, in the first place, usually larger, and are always more or less convex, 
instead of depressed in front, and their wall, whatever may be its condition in the 
barren or zooecial cells, is always thickly punctate, as if to afford greater facility for the 
aeration of their contents. In the ooecial cells also the median pore is always placed 
close below the orifice, 1 and is always formed originally by the upgrowth and eventual 
coalescence of two tubercular elevations, one on either side, by which a sort of preoral 
bridge of two arches is sometimes formed, beneath which is the median pore, and on 
the sides or lateral piers of the bridge is usually placed a minute avicularium. 
When decalcified the ooecial cell appears in the form of a thick walled sac, occupied 
by an ovoid finely granular mass resembling the contents of an ordinary ooecium. But 
1 Adeona pectinata is an exception in this respect. 
(ZOOL. CHALL. EXP. — PART XXX.— 1884.) Gg 23 
