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THE VOYAGE OF H.M.S. CHALLENGER. 
The median pore, of small size, is circular and papilliform, and surmounted by a 
chitinous ring as in Tubucellaria. 
On a transverse section, or rather fracture, of one of the branches the cavities of four 
zooecia are exposed, varying of course in size according to the point at which the zooecium 
has been broken across. As well as can be seen in such a rude mode of preparation, each 
zooecial cavity appears to be divided into an anterior or superficial and a posterior or 
deeper chamber by a very delicate membranous septum. It would further seem that 
the posterior and somewhat larger of these chambers is the habitation of the polypide, 
and that into which the mouth opens, whilst the median pore appears to communicate 
with the anterior chamber through a very narrow passage. At any rate the dried remains 
of the polypide, with its vagino-parietal muscles, may be indistinctly discerned in the 
former ; and in the latter, a brownish mass of uncertain nature. 
On the dorsal aspect the surface is marked with the same delicate vibices as in front. 
Close behind the tubular portion of the lateral zooecia is a large circular opening with a 
tumid border, and in one or two instances appearing to present a crescentic valvular 
fold, which may probably represent a modified avicularium ; but this is very uncertain. 
Towards the lower end of the zoarium, on the dorsal aspect, radical tubes may be seen, 
entering the backs of the zooecia at uncertain points (fig. 2b). Though a very aberrant 
form, I do not see where this curious production can be more properly placed than near 
Tubucellaria, with which it appears to have closer affinities than with any other genus. 
The name is intended to indicate this connection. 
Family XVI. Onchoporid^e. 
Character. — Zoarium flexible, continuous, branched or lobate, ligulate or foliaceous, 
then unilaminar ; zooecia urceolate, ventricose. Orifice semicircular, with a straight entire 
lower lip. On the front, close below the orifice, a lunate fringed pore, and on each side 
an oblong or circular, perforated disc, with a raised border. 
The above characters appear to me to be sufficient to separate the few species included 
in this small group from the numerous other forms possessing a very similar lunate pore, 
even when combined with a similarly shaped orifice, as in the genus Microporella. 
But considering, as Mr. Hi neks truly remarks, that we do not know the physiological 
import of the lunate pore, and that the form of the mouth is common to a vast number 
of species, I am not at present inclined to agree with him in regarding these two 
characters, even in combination, as alone sufficient to justify the association of such other- 
wise very dissimilar forms as Onchopora sinclairii and Onchoporella ( Carbasea ) bomby- 
cina, Busk, &c., with the lepralian Microporellidae. 
The resemblance, however, between the zooecial characters in Onchopora bombyema 
