178 
THE VOYAGE OE H.M.S, CHALLENGER. 
Am/phius Jiuxleyi, n. sp. (PI. XLII. figs. 5-11). 
Sponge (PI. XLII. fig. 5) massive, lobate, attacked ; lobes axially excavated by a 
large deep cylindrical cloaca ; oscules situated on the summits of the lobes, each the 
scarcely constricted opening of the cloaca (PI. XLII. fig. 8); oscular margin membranous. 
Pores small, in sieves, which overlie the incurrent canals (PI. XLII. figs. 9-11).. Surface 
smooth, formed of a thin, now wrinkled, skin, supported by tangentially lying, scattered 
oxeas. Texture soft. 
Spicules. — I. Megasclere. 1. Oxea (PI. XLII. fig. 6), slender, cylindrical, points 
blunt or tornote ; 0’588 by 0'007 mm. 
II. Microsclere. 2. Amphiaster (PI. XLII, fig. 7), axis minute, cylindrical, actines 
slender, cylindrical, terminally tylote ; arranged in a whorl at each end of the axis, and 
with a single one continuing the direction of the axis ; total length 0’016 mm., of the 
axis 0'004 mm. 
CbZo?i7".— Nut-brown externally, yellowish-grey within. 
Habitat . — Off Api, New Hebrides; depth, 60 to 70 fathoms. 
Remarks . — There is a single entire specimen of this sponge ; it measures 68 mm. in 
height, 112 mm. in length, and 57 mm. in breadth. The largest oscule measures 9 mm. 
and 10 mm. along two rectangular axes, the smallest is about 4 mm. in diameter; the 
largest cloaca is 31 mm. in depth, the smallest 5 mm. The excurrent canals radiate 
from the cloacas, running more or less parallel to the curved upper surface of the lobes 
in which they lie. The ectosome is thin, not more than OT mm. thick ; it consists of 
what might be called fibrous sarcenchyma, i.e., a granular deeply staining matrix, con- 
taining fusiform cells about 0'04 mm. in length. Notwithstanding the markedly brown 
colour of the skin, I could detect no special pigment-cells. The ectosome passes 
insensibly into the choanosome, the mesoderm of which is sarcenchymatous. The 
flagellated chambers are diplodal with short prosodi, they measure 0‘0237 mm. in diameter. 
The water-canals are provided with velar diaphragms. 
The oxeas are partly scattered singly through the sponge, partly loosely aggregated 
into narrow fibres, but never bound together by spongin. The fibrous spicular tracts 
appear fo run more or less parallel to the chief water-canals. The tangential spicules of 
the - ectosome partly consist of the most superficially situated of the singly scattered 
oxeas, and are partly provided by the spicular fibres which curve from the radial to. the 
tangential position as they approach the surface. 
