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XXX. On the Anatomical Characters of an Australian species of Perophora. By Jonn 
Denis MACDONALD, F.R.S., Assistant-Surgeon of H.M.S. * Herald, commanded by 
Captain H. M. DENHAM, R.N., F.R.S. Communicated by GEORGE BUSK, Esq., F.R.S., 
PLS. 
Read February 17th, 1859. 
DURING our stay at King George’s Sound, the dredge obtained several specimens 
of a very interesting compound Tunicary, belonging to the “social” division so called, 
and which I believe to be a new species of the genus Perophora. The points in which it 
differs from the known species appear to me to be too trifling to warrant the fabrication 
of a new genus for its reception. I shall therefore name it Perophora Hutchisoni, after its 
first discoverer, Lieut. John Hutchison, R.N. 
The zooids are about one-fifth of an inch in length, pyriform in shape, and supported on 
alternate tubular foot-stalks of a corneous texture, with one or more transverse articula- 
tions. These pedicels are continuous at their base with a tubular axis, from which they 
appear to be derived by simple extension of its walls without articulation. 
The principal trunk in the specimen before me is firmly fixed upon a sprig of Amphi- 
bolis antarctica, over which its rather irregularly-divided branches extend themselves, 
occasionally drooping freely, like the tender sprays of a climbing plant. 
No articulations are anywhere to be found except in the pedicels of the zooids, whose 
test commences at a definite line, where the corneous tissue of the pedicels terminates. 
The test is finely coated over with a minute siliceous grit interspersed with Forami- 
nifera and calcareous atoms. 
When all these adhering particles are removed by cautious immersion in dilute nitric 
acid, which destroys all the carbonate of lime and loosens the attachment of the siliceous 
elements, their impressions are left on the surface of the test, and here and there on that 
of the axis, which thence presents a deeply pitted appearance. 
The internal surface of the tubular axis is lined throughout with a very distinct epi- 
thelial membrane, obviously connected with its nutrition ; and in the little buds, which 
spring, botanically speaking, in the indefinite mode, from the growing branches, the 
cecal dilatation of the rudimentary test is lined with an extension of the same membrane. 
This lining, however, is not to be confounded with the true pallio-vascular system which 
is contained within it, and consists of a simple branched tube exactly corresponding with 
the trunks and ramifications of the corneous axis, while the coats of the tubules which 
enter the pedicels of the zooids are continuous with the mantle. Thence results a sort of 
“ cænosare,” exhibiting a remarkable analogy to that of the Sertularians, an analogy which 
us axis just described. This, however, 
is still further sustained by the nature of the sclero a 
may be regarded as perfectly homologous with the repent tubes and free pedicels of 
Laguncula, Pedicellina, and other Polyzoa. 
The branchial and cloacal openings present little or no external 
VOL. XXII. 
prominence, and are 
8 D 
