12 
THE VOYAGE OF H.M.S. CHALLENGER. 
Halecium beanii, Johnston (Pl. XII. figs. 3, 3a). 
Halecium beanii, Johnston, Brit. Zooph.., ed. 2, p. 59, pl. ix. 
„ „ Hincks, Brit. Hydroid Zooph., p. 224, pl. xliii. fig. 2. 
Trophosome. — Hydrocaulus attaining a height of three inches ; main stem and 
principal branches fascicled, becoming monosiphonic distally ; main stem irregularly 
branched, the smaller ramuli pinnately disposed, and for the most part carrying secondary 
and tertiary pinnae, ultimate ramuli very slender. Hydrophores commencing with a 
short basal offset from the distal end of each internode, and almost always continued 
by a consecutive series of short superimposed tubes, each slightly widening upwards and 
ending in a narrow everted limbus. 
Gonosome. — Gonangia springing each by a very narrow base from the side of an 
internode close to the origin of a hydrophore ; female slipper-shaped, with tubular lateral 
orifice ; male elongate, ovoid, with terminal orifice. 1 
Locality. — Station 75, off the Azores ; lat. 38° 38' 0" N., long. 28° 28' 30" W.; depth, 
450 fathoms. 
Station 163a, off Twofold Bay; lat. 36° 59' S., long. 150° 20' E.; depth, 150 fathoms. 
The slenderness of the ramuli in the monosiphonic portion of the colony and the 
slipper-shape form of the female gonangia afford distinguishing characteristics of the 
present species. The general ramification of the colony is in a single plane, and 
the ramuli spring each from a point on the side of an internode close to the base of 
a hydrophore. The number of superimposed segments in the hydrophore is usually 
very considerable and may amount to as many as seven or eight. The limbus of the 
hydrophore, though narrow, possesses the wreath of brilliant puncta characteristic of the 
genus and its allies. 
The slipper-shaped form of the female gonangia, though this condition is not confined 
to the present species, is remarkable and characteristic. The quadrate orifice, instead 
of being as in most cases terminal, is here placed near the middle of the side which 
faces the branch, and is raised upon the summit of a short tube. The point from 
which the gonangium springs is situated close to the origin of a hydrophore, and 
corresponds exactly to the origin of a branch whose place is thus taken by the 
gonangium. 
Halecium beanii is one of the few British Hydroids brought home by the Challenger. 
It was obtained during the voyage from two localities ; one of these was in the neighbour- 
hood of the Azores, where it occurred at a depth of 450 fathoms, the other off the south- 
east coast of Australia at a depth of 150 fathoms. 
1 As seen in European specimens. No male gonosome occurs among the specimens of Halecium beanii brought 
home by the Challenger. 
