44 AGLAOPHENIA DISTANS. 
the same point of origin, the twin branches then directing themselves 
forwards and remaining nearly parallel to one another. 
The hydrothecz are so closely set that the summit of each is on a 
level with the base of the next above it. 
This species closely resembles the preceding, A. gracilis, of which it 
may possibly be regarded as a variety. 
Aglaophenia distans. 
Pl. XXVI. Figs. 1-8. 
Trophosome.— Hydrocaulus attainmg a height of about four inches, sim- 
ple, rooted by an entangled bunch of tubular filaments, fascicled below, 
becoming non-fascicled above, and here divided into equal internodes, 
each of which carries a pinna on alternate sides; pinne distant, attain- 
ing the length of nearly an inch. Hydrothecx deep, nearly cylindrical 
above, narrowed below; margin crenate, with a single long tooth-like process 
in front ; intrathecal ridge not conspicuous. Supracalycine nematophores 
not overtopping the hydrotheca ; mesial nematophore attaining about a 
third of the height of the hydrotheca, to which it is adnate for its entire 
leneth. 
Gonosome.— Corbulze composed of numerous pairs of ribs, which are 
quite free from one another, each carrying a small hydrotheca near its 
origin, and having numerous tooth-like nematophores along its distal 
edge; peduncle of corbula rather long, carrying three hydrothece. 
Dredged off Pacific Reef, from a depth of 283 fathoms. 
The present species is rendered very distinct by the long tooth-like 
process on the front margin of the hydrotheca, and by its remarkable 
open corbule. The form of the hydrotheca is not absolutely constant, 
and occasionally there may be seen on the same pinna with the ordi- 
nary form others in which the narrowing of the hydrotheca towards 
the base is much less marked. (Fig. 4.) 
The corbulx, which closely resemble those of Aglaophenia bispinosa, are 
in the highest degree instructive, and afford a beautiful example of 
morphological transformation. Like the corbule of other species they 
are metamorphosed pinne, but the change here undergone is of such a 
character as to bring out very distinctly their true morphology. The 
pinna (Fig.) 7, which is here to become a corbula, retains nearly its ordi- 
