36 THE VOYAGE OF H.M.S. CHALLENGER. 
nematophore of Aglaophenia macgilivray, though large, is very far from attaining 
the width of the hydrotheea to which it is attached, and does not, either in size or form, 
depart so much from the normal condition as to justify us in assuming it as the ground 
on which to base a distinct seetion of the phylactocarpal Plumularide (Aglaophenia of 
Kirchenpauer in its widest sense) ; and the remaining small number of species which 
Kirchenpauer places in his Pachyrhynchia do not seem to afford any stronger grounds than 
Aglaophenia macgillivray? for the creation of a separate systematic group. In the long 
corbula, with its closely adnate costa and parietal ridges, and in the even margin of the 
hydrotheca, more important differences may perhaps be recognised, but still nothing to 
demand a separation from the other members of the genus. 
A closely allied if not identical form—the Aglaophenia cupressina of Lamouroux, has 
been identified by Kirchenpauer with a Plumularian brought by Semper from the Pelew 
Islands, where, according to Semper, it is known by a vernacular name suggested by its 
stinging properties. Another of the Challenger species (Lytocarpus secundus, see below, 
p. 42), likewise brought by Semper from the Pelew Islands, would seem, according to 
the report of it given by this zoologist to Kirchenpauer, to be also one of those Hydroids 
whose formidable stinging powers cause it to be dreaded by the natives. 
Aglaophenia macgillivray attains a size greater than that of any other Ag/aophenia 
with which I am acquainted. Though the specimen from which the drawing has been 
made had lost a portion of its proximal end, what remains of the colony measures in 
height fifteen inches. 
Dredged at Zamboanga, Philippines, 30th January 1875, from a depth of 10 fathoms, 
Aglaophenia filicula, n. sp. (Pl. XI. figs. 1-6). 
Trophosome.—Colony attaining a height of about three ches ; stem monosiphonie, 
simple, rooted by a creeping tubular fibre ; hydrocladia about one-fourth of an inch in 
leneth, alternate. Hydrothecee deep, thimble-shaped, margin serrated, with the median 
tooth slightly longer than the lateral teeth; intrathecal ridge near the base of the 
hydrotheca, extending obliquely forwards and upwards ; mesial nematophore adnate to 
the walls of the hydrotheca for about three-fourths of their height, and then becoming 
free as a beak-like process which scarcely overtops the margin ; lateral nematophores 
tubular, overtopping the margin of the hydrotheca. 
Gonosome.—Corbule somewhat crescentic, with about seven pairs of costee, which are 
adnate to one another by their edges, with a row of tubular denticles at the lines of junc- 
tion, and with a spur-like denticle at the proximal end of each row; a single free costa 
with dentated edges at the proximal end of the corbula. 
Other corbulz having the costze all free occur in the same colony. 
The simple stems of Aglaophenia filicula spring from the creeping hydrorhiza, in 
