340 WILSON. : [Vou. IX. 
directly with the afferent canals on the one side and the 
efferent canals on the other, as may be gathered from PI. 
XXII, Fig. 98, representing a small portion of the mesoderm of 
the sponge. Efferent canals are abundant round the edge of 
the spongy regions (Figs. 95 and 97), and communicate with 
the larger efferent canals lying in the heart of the gelatinous 
tissue. In the body of the sponge the main efferent canals 
pursue an irregular course, but in the oscular papillae they run 
longitudinally, there being at the base of the papilla several 
which gradually run into one another as they near the summit 
of the papilla. There is usually one canal in the axis of the 
papilla, which is larger than the rest and may be considered 
the main canal of the papilla. 
The gelatinous tissue is much like that of Tedania, consist- 
ing of a network of cells with a watery jelly in the meshes. 
As in Tedania, there is an abundance of delicate bipolar cells, 
the processes of which are long, slender, and branching. There 
are also numerous large granular cells, not present in Tedania. 
Pl. XXIII, Fig. 99, is a small portion of a section showing the 
gelatinous tissue lying between two canals (c. w.=canal wall). 
The general arrangement of the skeleton is shown in Pl. 
XXII, Fig. 97. The brushes of spicules supporting the dermal 
membrane, the radial and tangential bundles, and the distribu- 
tion of the free spicules, need no further description. Where the 
gelatinous tissue comes to the surface, the brushes of spicules 
supporting the dermal membrane are either absent, or feebly 
developed. The skeletogenous oxea is very often found with its 
two ends modified after the fashion shown in Pl. XXII, Fig. 
101. The length of the process x varies considerably. What 
few tylotes occur are found either in the dermal membrane or in 
the brushes supporting it. I have seen three or four tylotes 
with nicked heads like those of Tedania. As in Tedania, the 
microscleres are most abundant round the walls of the efferent 
canals, but while they are larger than the microscleres of 
Tedania, they are much less numerous. It may be mentioned 
that after hunting persistently through many sections and 
caustic potash preparations of this sponge, I have found four 
anchors, varying in size but otherwise alike. Being unable to 
