158 BULLETIN OF THE BUREAU OF FISHERIES. 
Skeletal framework.—The skeleton of the incrustations consists of a horny basal plate bearing closely 
set vertical horny columns from which megascleres project. From near the apex of each horny column 
a few large, smooth, and slightly curved styles project, forming a well-marked tuft. These styles 
measure 160 to 4oou by 8 to rou. The longest styles lie near the apex of the column, and some of 
them project beyond the surface of the sponge. Mingled with the mature styles are younger spicules 
of the same type, but slenderer and shorter. Projecting from the sides of some of the larger horny 
columns are a few small styles, 80” by 5 to 6u, some of them distinctly spinose, others with few and 
feeble spinulations. The skeleton of the incrustations contains longer styles than are found in the lobes 
of specimens like figure 36 or in the branches of older specimens like figure 35. In the incrustations we 
found a good many styles measuring 5oou long, while in the lobes and branches of older specimens 
they rarely exceed 380 in length. n 
The skeleton of the constituent branches in a specimen like figure 35 consists of a reticulum of 
horny spiculo-fiber (Pl. L-XII, figs. 31 and 33) which breaks up near the surface into independent radial 
fibers that extend out to and support the dermal membrane. From near the apex of such a radial fiber 
a few large, smooth, slightly curved styles project, forming a well-marked tuft. The longest styles 
are found near the surface, and many of them project beyond the surface of the sponge. These large 
styles average about 3304 by rou. Projecting vertically and obliquely from the sides of the radial 
fibers are large, smooth styles similar to those near the apex and a few small distinctly spinose styles 
(about Sou by 7), together with others of about the same size but with few spinulations. It is these 
small styles which represent the echinating spicules of the subfamily. The spiculo-fibers of the inte- 
rior bear similar echinating spicules. Wilson has pointed out that “‘the projecting (echinating) styles 
are few and scattered, spinose or smooth, the two types intergrading. The spinose type has numerous 
distinct though small spinulations on the shaft and a minutely tuberculate head. Spicules with only 
a few scattered spines occur, and, finally, quite smooth spicules with head end simply rounded and 
not enlarged.” 
The description given above applies both to the lobes of young specimens and the constituent 
branches of older ones. The skeleton of the older specimens (Pl. L-XIII, fig. 35) differs, however, 
from that of the younger (fig. 36) in the following details. The spiculo-fibers in the former are consid- 
erably thicker than in the latter, due to the increased accumulation of spongin, and the styles reach 
a greater thickness. Some styles in the older sponge were found to measure 16uin diameter while the 
greatest thickness observed in the younger sponge was 14u. The small echinating styles are also more 
abundant in the former. 
Family AXINELLIDA. 
Sponge body ordinarily more or less upright, of a branching, lamellate, or cuplike 
habitus. But massive and even incrusting forms occur. Skeleton typically consists 
of ascending bundles of spiculo-fibers, from which arise subsidiary fibers that radiate to 
the surface. Skeletal fibers without spined echinating spicules, and typically plumose. 
The characteristic megascleres are monactinal. In addition to these, diactinal mega- 
scleres may also occur, and in some genera are the only form. Microscleres in the shape 
of microxeas, trichodragmata, or sigmata occur in a few genera; cheloid microscleres do 
not occur. 
Axinella O. Schmidt. 
Sponge body typically ramose; habitus varies, however, but while sometimes 
lamellate it is noc cuplike. There is a firmer axial skeleton from which radial fibers 
pass to the surface. Axial skeleton not massive, but made up of ramifying and anasto- 
mosing spiculo-fibers. The radial fibers, which terminate in brushes of diverging 
smaller spicules, are joined by numerous short transverse connectives, the genus 
differing in this point from Phakellia in which the radial fibers are comparatively free. 
Skeletal fiber more or less distinctly plumose. Megascleres chiefly styles, but strongyles 
and oxeas may occur; scattered acanthostyles may also occur sparsely, as a vestigial 
feature. Microscleres generally absent, but trichodragmata are present in some species. 
