152 BULLETIN OF THE BUREAU OF FISHERIES. 
Subfamily PHL@ODICTYINA. 
Sponge body provided with fistular outgrowths. Characteristically the ectosomal 
skeleton is much denser than the choanosomal, constituting a sort of rind. The micro- 
scleres are often absent. 
Phloeodictyon Carter. 
Spongin usually present, but the skeleton is not a reticulum of distinctly chalinine 
spiculo-fiber. Megascleres, oxeas varying to strongyles. There are no microscleres. 
Phleeodictyon nodosum n. sp. (Pl. LXII, figs. 29, 30, 32; Pl. LXVI, fig. 63.) 
One specimen dredged in Beaufort Harbor. 
Slender fistulz, 30 to 35 millimeters high and 1.5 to 3 millimeters in diameter, rounded off and 
closed terminally, connect with a basal portion which is attached to a piece of shell. The basal portion 
isincomplete. As it stands it consists of an incrusting part on the upper surface and a somewhat thicker, 
2 to 3 millimeters thick, torn part on the under surface of the shell. The entire sponge was probably 
not large. The shell is probably to be looked on as having been surrounded by, and incorporated in, 
the upper part of the sponge body. 
Color, in alcohol, whitish brown. Wall of fistule thin, but firm. Many sand grains and pieces 
of shell have been incorporated by the sponge. 
The dermal membrane of the fistular wall is perforated by pores lying in the meshes of the skeletal 
reticulum. Many of the pores are closed, and those that are not closed are probably only partly 
open. They measure 12 to 16 w in diameter. The membrane is thin, contains only a few granular 
amcebocytes, and is favorable for histological study. Some few foreign incrustations cling to it, among 
them holothurian (synaptid) spicules such as Bowerbank has figured (1864, Pl. V, figs. r19, 120). 
Pores and oscula over basal part of sponge uncertain. This part exhibits a good many small canals, 
1zoto 5scouindiameter. Flagellated chambers spheroidal, or about so, 28 w in diameter. The ectosome 
of the fistular wall includes a great many small, rounded subdermal cavities, about 60 to roo u in diam- 
eter as seen in cross sections of the fistula (PI. LXII, fig. 30). Internal to the ectosomal skeleton, the 
fistula is collenchymatous and is excavated by a large axial canal around which lie smaller canals, 
which yet are of good size, about 150 to 350 m in diameter (fig. 30). These are separated by thin sheets 
and strands of sponge tissue. 
All the fistule are closed terminally, showing no sign of oscula. If ordinary oscula were present 
in life, one would expect to see some sign of them in the preserved specimen. Perhaps the axial canal 
opens terminally through a sieve plate, the apertures of which, resembling pores, are now closed. As 
Lundbeck says (1902, p. 58), there is diversity of opinion with regard to the functioning of the fistule 
in these sponges. Living, or, at any rate, carefully preserved whole specimens need to be studied. 
The pores over the general surface and the subdermal cavities of the ectosome make it clear that water 
streams into the fistula. Nevertheless, perhaps the axial canal is efferent. It would seem that it must 
be so in species such as P. elongatum Tops., where it connects with the exterior by a terminal or sub- 
terminal aperture which has the appearance of being normal (Lundbeck, loc. cit., p. 60): 
Spicules.—Oxeas (Pl. LXVI, fig. 63) smooth, slender, slightly curved, subcylindrical, tapering 
gradually to sharp points, about r00 nz by 4to 54. The strongylate modification occurs. 
Skeletal framework of the fistule.—The ectosomal skeleton includes the usual parts, a dermal layer 
of tangential spicules and a subjacent layer of spiculo-fiber. 
The dermal spicules intercross in all directions, constituting a layer which is, in general, single, 
although in places parts of two or three spicules may be superposed. The spicules form a reticulum 
(Pl. LXII, fig. 32), at the nodal points of which they are heid in place by spongin. These nodal points 
in astained preparation of the wall are conspicuous. Meshes of the reticulum triangular or polygonal; 
side of a mesh the length of aspicule or less and formed by one, or, in places where the spicules are more 
abundant, by several, about two to five, spicules. In regions of the latter character the spicules are so 
closely grouped that they radiate from many of the nodal points, like spokes of a wheel. Elsewhere 
in the same fistula the reticulum may be unispicular. 
