Dr. J. E. Gray on Hyalonemata. 273 
there are concentric ridges edged with a series of spines that 
are directed towards the middle of the length of the spicule. 
(Schultze, t. 2. f. 4,5). These spicules are lengthened as the 
coral grows. 
The corals live erect at the bottom of the sea, with the free 
part of the spicules sunk in the mud or sand. 
The upper part of the coral is often taken possession of by 
a cup-shaped parasitic sponge (Carteria). ‘The sponge de- 
stroys the polypes; and the ends of the spicules form a short 
rapidly tapering cone, which is separated from the sponge 
by a number of spicules felted together, forming a hard case 
which separates the end of the coil from the rest of the sponge. 
The coils of spicules, as left when the polypes die and the 
bark has rotted or been eaten away by fishes, &c., are often 
found in the sea, as are also the separate spicules. 
M. Bocage makes a statement that is otherwise difficult 
to understand. He says, ‘“‘ I have several specimens of Hyalo- 
nema with other parasites: two are covered with an Antipa- 
tharian, three absolutely destitute of polypes and sponges, 
one embraced by the foot of an Actinia of what seems to me a 
new species.” (Ann. & Mag. Nat. Hist. ser. 4. vol. i. p. 37.) 
Dr. Semper has lately named a single specimen of Hyalonema 
he reeeived from the Philippines H. Schultze?, because it is 
destitute of polypes and bark, but attached to a sponge. 
They have been found in a fossil state in Mountain Limestone, 
retaining the siliceous character of the coil. 
HyaLoneMA, Gray, Proc. Zool. Soc. 1835, p. 64; Ann. & 
Mag. Nat. Hist. 1850, vi. p. 306; P. Z. 8S. 1867, p. 118 
(not Lovén, Ann. & Mag. N. H. 1868, p. 90); Brandt, Sym- 
bol. 14 (1859); Wyville Thomson, Intell. Observ. 1867, p.81. 
Hyalocheta, Brandt, Bull. Acad. Pétersb. 1857, p. 17; Symbol. 17 (1859). 
Bark sandy. Polypes cylindrical when contracted. Tenta- 
cles 20. 
1. Hyalonema Sieboldit, Gray, P. Z. S. 1835, p. 65, &e. BM. 
H. mirabilis, Gray, P. Z. 8.1857, p. 279; Bowerbank, P. Z. 8. 1867, p. 18; 
Loyén, Ann. & Mag. N. H. 1868, p. 90. 
Type, without parasitic sponge on apex :— 
H. Sieboldit, Brandt, Symbol. t. 1. f.1; Wyville Thomson, Intell. Obsery. 
1867, p. 93, f. 1. ' 
Var. Possieti. Polypes produced and clustered. 
Hyalocheta Possieti, Brandt, Symbol. t. 2. f. 6-20. 
separate the siliceous spicules of zoanthoid polypes from the spicules of 
sponges. 
