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of this genus described by Ralfs in ‘ Pritchard,’ as seemed provi- 
sionally, at least, to justify a distinct designation. This form 
could not be confounded with E. Brightwellii, in which, according 
to Ralfs’ description, the lower margin is concave; whereas in the 
present case the outline of the lower margin is convex, in which 
particular it resembles E. gibba. Compared with this latter the 
form in question is relatively broader, the outer margin being 
regularly semicircular. In E. gibba the ends are somewhat pro- 
duced. In this case it will be observed that towards the extre- 
mities the dorsal margin bends inwards towards the ventral. In 
the course of the examination several examples were met with, and 
they ever presented the same outline. The sculpture of the valve, 
as in the other two forms of the genus, is punctate, but instead 
of being arranged in concentric lines, as is the case with E. 
Brightwellii and E. gibba, the puncta are dense, and towards 
either extremity arranged in parallel lines across the valve; 
towards the middle it was impossible to observe satisfactorily 
the arrangement of the puncta. This form Mr. O’Meara pro- 
posed to name Euodia Chimmoana. In connection with the form 
he also took occasion to refer to a remark of Ralfs, who doubts 
“ whether Hemidiscus be distinct from Euodia, since the only dis- 
tinction seems to be the marginal nodule of the former — a cha- 
racter perhaps overlooked by Professor Bailey.” In the numerous 
specimens which came under notice there was no appearance of 
a nodule in the ventral margin — a fact which confirms the accu- 
racy of Bailey’s description of E. gibba. 
Professor E. Perceval AVright exhibited mounted specimens of 
the Polyps of Tubipora musica. The animal of the Organ Pipe 
Coral has been up to the present moment almost unknown. The 
figures of its structure, as given by Quoy and Gaimard, have 
been copied from book to book, and the details of that structure, 
as given by these same authors, are, to say the least, meagre and 
unsatisfactory. Dr. ANTright looked for a long time in vain for 
living specimens of this Alcyonarian in the Seychelles, dredging 
for it in deep and shallow water ; and while feeling sure it was 
not far off (from the fresh-looking specimens that very frequently 
came ashore), searching for it without success, until an accidtnt 
revealed its peculiar habitat, and then it was found in great quan- 
tities. One day, during the prevalence of a “Grande Maree,” 
while wading up to his waist on the edge of the coral reef off the 
north-west side of He Curieuse, his foot sunk into a substance 
which conveyed to him quite a different sensation from either the 
slippery Alcyonaria or the sharp-edged brittle Zoantharian Corals, 
and gathering up some of it with a landing-net, he fountl he had 
put his foot upon a mass of Tubipora musica. Prom that time 
he had no difficulty in finding any quantity, nor in coming to the 
conclusion that the Tubipora lived as a parasite on the Zoantha- 
rian Corals, just at the borders of low water. The observations 
made then he hoped to give in detail elsewhere, even though 
on his return home he found that Professor Kolliker had been 
