No. 3.] DEVELOPMENT OF MARINE SPONGES. 339 
everywhere beneath a dermal membrane.  Spicules, stout 
skeletogenous oxeas, ,%3, 
microscleres (oxeas) of varying length; also a few tylotes. 
mm. long and often slightly bent ; 
Dermal membrane strewn with oxeas of full size, amongst 
which are scattered microscleres, with here and there a tylote. 
Membrane supported by brushes of oxeas containing a very 
few tylotes. Spongy tissue contains radial skeletal bundles, 
composed of oxeas, running in from the brushes ; bundles com- 
posed of same spicules crossing the former at right angles 
some little distance below the surface ; and numbers of oxeas 
scattered freely through the tissue in such a way that they 
cross one another in every direction, but are not cemented 
together to form a network. Gelatinous tissue contains both 
ordinary oxeas and microscleres scattered freely about, micros- 
cleres most abundant immediately round main efferent canals. 
Green Turtle Cay, Bahamas. 
Tedanione foetida is found in the “ sounds’ 
5] 
on the roots of 
the mangrove. The surface of the sponge is furrowed in a 
manner recalling the surface of Tedania, but the furrows are 
not nearly so abundant nor conspicuous as in the latter genus. 
On cutting the sponge open it is seen that the body is divided 
as in Tedania into spongy and gelatinous tracts, the gelatinous 
tissue lying around the main efferent canals. But it is only 
occasionally that the gelatinous tissue comes to the surface. 
In most places it lies in the interior completely covered by 
spongy tissue. In Pl. XXII, Fig. 96, a vertical section through 
the base of the sponge is shown, and it is seen that the 
gelatinous tissue is wholly in the interior of the body. In PI. 
XXII, Fig. 95, a transverse section through an oscular papilla 
is shown, and here the resemblance to Tedania is greater, for 
the gelatinous tissue comes to the surface in several places. 
The dermal membrane is strengthened by numerous oxeas 
of full size, Pl. XXIII, Fig. 100, and the pores are few and 
scattered. Pl. XXII, Fig. 97, represents a section vertical to 
the surface, and shows the gross features of the canal system. 
The subdermal cavities are numerous and open into larger or 
smaller afferent canals, by which the water is introduced into 
the spongy regions. The flagellated chambers communicate 
