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THE VOYAGE OF H.M.S. CHALLENGER. 
into two, and on either side, close to the angles of the mouth, a minute immersed 
avicularium. Avicularian cells mostly marginal, but sometimes interspersed amongst the 
others, with a long spear-shaped acute mandible. 
Habitat. — Station 190, lat. 8° 56' S., long. 136° 5' E., 49 fathoms, green mud. 
It is not improbable that this species may be identical with Mr. Haswell’s Eschara hexa- 
gonalis, and not impossibly with M. Milne-Edwards’ Eschara lichenoides, but the 
published materials are insufficient to determine the point. All difficulty however would 
at once be removed by the examination of the chitinous parts, and especially of the 
zocecial opercula, which are of very peculiar and remarkable conformation in the present 
species, as will be seen in the figures. 
(4) Adeonella atlantica, n. sp. (PI. XX. fig. 7, woodcut 54). 
Character. — Zoarium branched, branches expanded and bifid at the end. Cells 
trimorphous. Zocecial, narrow, ovate, truncated at bottom ; surface convex, rising into 
a rounded eminence below ; sparsely punctured round the border and in three or four 
longitudinal rows in front. Orifice elliptical, raised, peristome sometimes cucullate. 
Median pore large, simple, circular, much depressed ; a large avicularium on one side 
directed obliquely upwards and inwards towards the 
middle of the orifice over which it slightly projects ; often 
a smaller avicularium on the opposite side near the orifice. 
Habitat. — Stations 135 a and c, off Inaccessible and 
N ightingale Islands, Tristan da Cunha, 7 5 and 110 fathoms. 
[Tierra del Fuego, 19 fathoms, Darwin; South 
Africa? Miss Gatty ; ? Gulf of Florida, 10 to 18 fathoms, 
Pourtales.] 
I have inserted the last locality in some doubt whether 
the present species may not possibly be identical with Prof. Smitt’s Porina subsulcata 
(Florid. Bryoz., part ii. p. 28, pi. vi. figs. 136-140). One of the most obvious characters 
of the species is the usually large avicularium pointing upwards and inwards so as to project 
slightly over the lower border of the mouth ; another is the absence or comparative shallow- 
ness of the frontal depression and, when decorticated, the cribriform puncturation of the 
whole surface ; and a third, the usually subcrescentic form of the mouth in the zooecial 
cells ; the frontal pore appears in this species to be unconnected with the mouth. 
(5) Adeonella regularis, n. sp. (PI. XX. fig. 2, woodcut 55). 
Character. — Zoarium broadly lobate, thick. Cells disposed in very regular order, 
quincuncially, and separated by wide deep sulci, trimorphous. Zocecial, rhomboidal or 
square with an angle at top and bottom ; front very convex. In the natural state the 
