86 THE VOYAGE OF H.M.S. CHALLENGER. 
Duchassaing and Michelotti have regarded this species as being closely allied to 
Symphyllia grandis, Milne-Edwards and Haime, but a comparison of the description of 
this species with that of Symphyllia grandis will shew that the two forms are quite 
‘distinct, and not referable to the same genus. 
Locality.—Bermuda. 
6. Lsophyllia cylindrica (Duchassaing and Michelotti). 
Symphyllia cylindrica, Duchassaing and Michelotti, Mém. Cor. des Antilles, p. 71. 
A very fine series of specimens, apparently referable to this species, was obtained. The 
series shows clearly the different stages of growth, five specimens being simple, fixed 
forms, the youngest of which is about 5 mm. in diameter, circular, with very prominent 
septa and costee and a rudimentary wall, with three cycles complete; and the oldest 
about 2 cm. in diameter with five cycles complete, slightly oval in shape, irregular on 
one side where gemmation is taking place. Another small specimen shews an advanced 
stage in the formation of the colony, there beg two fully formed calicles and a third 
developing. The larger specimens are elongated and broadly pedunculate; on these 
an incomplete epitheca is present, and the walls are fused throughout but often flattened 
above, presenting a decided approach to Isophyllia marginata. The ealicles tend to 
isolate themselves, but are generally in irregular series of from two to four. The septa are 
of very variable size, and generally much thickened, more especially the primaries and 
secondaries (more clearly seen in the young stages); the teeth are strong but not specially 
developed at the upper margin. ‘There are about seven or eight large septa to the 
centimetre with often one or two very small additional ones. The columella is moderately 
developed, but not abundant, and not continued from centre to centre. The width of 
the calicles is about 20 mm. and the depth from about 8 to 10 mm. 
A single rather small specimen, which does not seem distinct from this species, differs 
in being flattened, apparently free at the base, and in having thinner septa. The species 
is very close both to the Isophyllia dipsacea and to Isophyllia marginata, and there are 
a few forms which seem so nearly intermediate between them, that it is with much doubt 
that I have retained the species. 
Locality.—Bermuda. 
7. Lsophyllia knot (Duchassaing and Michelotti). 
Symphyllia knoxwi, Duchassaing and Michelotti, Mém. Cor, des Antilles, p. 71. 
This specimen agrees well with the description given by Duchassaing and Michelotti, 
The most striking feature is the degree of separation of the calicles, which tend rapidly to 
