38 
THE VOYAGE OF H.M.S. CHALLENGER. 
7. Bugula margaritifera, n. sp. (PL VIII. fig. 4). 
§ 8. Those in which the zocecia are wholly unarmed, such as Bugula {Halophila) 
johnstonice. 
8. Bugula neritina (Linne). 
9. Bugula {Halophila) longissima, n. sp. (PL XXXI. fig. 7). 
It may also he observed that the first and second of these groups consist almost 
exclusively of very deep water forms, the shallowest being 150 fathoms for Bugula 
sinuosa, whilst the depths from which the other species, included in those groups, were 
brought up was on the average not less than 2000 fathoms. They would appear there- 
fore to constitute a distinctively abyssal type. 
The Challenger collection contributes eight new species to this genus, of which 
perhaps from sixteen to twenty were previously known. 
Of these, two occurred in the South Atlantic region, two in the Kerguelen, or 
South Indian region, two in the North Atlantic, and one in both the South Atlantic 
and South Pacific regions. 
The least depth from which any one of them was brought up is 60-75 fathoms; 
the depths from which all the rest were procured varying from 400 to 2500 fathoms ; and 
as the species from 600 fathoms occurred also in the South Pacific, at a depth of 2160 
fathoms, they may, as above said, be regarded as specially deep water forms ; on which 
account, doubtless, they have hitherto escaped notice. 
Though none appear to have been met with in the Australian region, Bugula bicornis 
occurred but very little to the west of it. The group affords a striking instance of the 
comparatively large size and free growth, and at the same time of the extremely delicate 
structure, characteristic it may almost be said of the Polyzoa that live in the tranquil 
depths of the ocean. 
(1) Bugula versicolor, n. sp. (Pl. III. fig. 4). 
Character . — Zoarium about 2 inches high; coloured blue and purple; 1 forked, and from 
the upper side only of each branch straight secondary branches arise in the same plane 
and parallel with each other. (Candelabriform). Zocecia bi- or tri- serial, oblong, nearly 
straight on the outer side, sinuated on the inner. Aperture entire, margin thick, smooth. 
Ooecia globose, usually seated on one of the median zocecia in the triserial branches, and 
enclosed within the superjacent zocecium, which is widely dilated for its reception. 
Habitat. — Station 23, Sombrero Island, 450 fathoms, Globigerina ooze. Station 122, 
lat. 9° 5' S., long. 34° 50' W., 350 fathoms, red mud. 
1 This colour has remained permanent in a wet preparation up to the present time (1884). 
