SPONGES 64 
Scarlet Sponge ( Aimphimedon yariabilis D. and M.). This sponge is made 
up largely of fiber which is almost paper-like in consistency, and which be- 
comes very white upon exposure to thesun. These fibers are quite flat, and 
are supplemented by numerous, very small and fine needle-like spicules. The 
form of this sponge is quite irregular, depending somewhat upon the exact spot 
in which it grows, That given in Vig. 19 has mound-like projections from 
which open the excurrent tubes, but these become larger in the beautiful 
colored specimen given on plate IV. 
On page 35, B, [have given a portion of the Branching Sponge ( Chal- 
inula oculata Bow. ) of our New England coast. This species has a fine mesh- 
like skeleton upon which there is little sarcode at any time. The larger orifices 
seen in the cut are the excurrent, the incurrent being very small. This sponge 
shows the branching form of a Spiculigenous Sponge, a form which is also as- 
sumed by the Horny Sponges. (See A, incuton page 35.) The branches of 
the Chalinula anastomose where they come in contact. 
On page 38, Fig. 28, is given acut of the cup form ofa Spiculigenous 
Sponge. ‘This species has coarse fibers which run longitudinally with short, 
cross connecting fibers. The long fibers turn outward at their extremeties. 
‘See Fig. 33, B, page 61.) This spenge is quite variable in form when young, 
or when placed under circumstances which are not favorable for its develop- 
ment. At such times, a portion of the cup-like form only is developed. 
When fully grown, this sponge measures ten inches in diameter and about 
the same in height. Thisis called the Gray Cup Sponge ( Cribrochalina in- 
