72 
THE VOYAGE OF H.M.S. CHALLENGER. 
below, composed of a thickish membrane supported on tbe inner face by a strong chitinous 
bow having a projecting process near each lower angle for the attachment of the occlusor 
muscles. Ooecia represented by a small chamber in the upper part of the cell, which opens 
above the oral orifice. 
Few questions have given rise to more disputation and confusion than as to what 
should be understood under the term Vincularia. I am not, however, here prepared to 
enter into this vexata qucestio, with respect to which some useful remarks by Mr. Hincks 
will be found in one of his communications on the Family Microporidse. 1 
The above definition, therefore, is only proposed provisionally, and it is here intended to 
restrict the term to cylindrical or rather polygonal, continuous growths, partaking of the 
characters of Microporci and Stegcmoporella, and intermediate, as it were, between those 
two genera, and forming with them the Family Microporidse ; differing from Microporci 
chiefly in the conformation of the oral orifice and the absence of distinct ooecia, and from 
Steganoporella in the cavity of the zooecium not being divided into two chambers, in the 
incompleteness of the operculum, and its simpler chitinous framework, the absence of 
the two suboral chitinous trabeculae, &c 
(l) Vincularia gothica, d’Orbigny (PI. XXIII. fig. 1). 
Vincularia gotliica , d’Orb., Palseont. Frang., p. 68, pi. dcliv. tigs. 13-16. 
„ novce hollandice, Haswell, Proc. Linn. Soc. New South Wales, p. 41, pi. iii. fig. 3. 
„ steganoporoides, 2 Macgilliv., New Species of Bryozoa from the Marion Islands, Proc. 
Roy. Soc. Victoria, June 1881, p. 6, pi. ii. fig. 5. 
Character. — Zoarium furcately branched, octagonal. Zooecia elongate, arched above, 
straightly truncate at bottom ; border smooth. Primary or epithecal orifice semicircular 
or subcrescentic. Lamina occupying the lower two-thirds 
of the area. Its upper border somewhat incurved. On a 
level with the upper border of the lamina a tooth-like 
process springs from each side of the zooecium, which 
gradually elongating meet in the mesial line, where they are 
joined by a median process or denticle, which rises gradually 
from the upper border of the lamina, thus forming a 
bridge with two arches and a thick central pier. Surface of 
bordering ridges and lamina perfectly smooth and imper- 
forate. Ooecia and avicularia 0. Operculum 0 //, 013 x '0085 incomplete below, membrane 
thick, supported on the inner face near the border by a very strong chitinous arched bow, 
1 Ann. and Mag. Nat. Hist., ser. 5, vol. ix., 1882, p. 119. 
2 Mr. Hincks (Gen. Hist. Mar. Polyz., Ann. and Mag. Nat. Hist., ser. 5, vol. ix. p. 119, 1882) seems to regard 
this as a form of his Steganoporella smittii (Brit. Mar. Polyz., vol. i. p. 178), which, however, I should myself refer to 
the genus Micropora. It is clearly quite distinct from Mr. Macgillivray’s species. 
