50 4 SPONGES 
species is dull orange or whitish. A black tar-like substance sometimes flows 
out of the excurrent orifices of some of the Horny Sponges which is probably 
the decaying flesh, and this has a very disagreeable odor. 
The Reef Sponge when placed in formalin, changes the liquid bright red, 
and some other sponges change color when dying and give out colored fluids. 
The Violet Sponge, already mentioned, gives out a violet fluid, and the sponge 
changes from greenish yellow to this color. ; 
The skeleton varies somewhat in color in different genera. | Commercial 
sponges have the skeleton, when unbleached, rather pale amber, but it must 
be always kept in mind that the skeletons of young sponges are lighter in col- 
or than adults, 
Sponges of the genus Verongia have the skeleton dark amber. The skel- 
eton of the Goat Sponges is very hght in color, often nearly white, and the 
same is true of the Net and Maynard Sponge, both of which belong to the ge- 
nus Stelaspongos, 
GEOGRAPHICAL RANGE ETC. OF HORNY SPONGES. 
Horny sponges do not occur north of Cape Hatteras and Bermuda in the 
west Atlantic. How far south they extend along the American coast has not 
been definitely ascertained, but probably to southern Brazil. On the eastern 
side of the Atlantic they have been found from England to the Cape of Good 
Hope. They also occur about Australia. 
On the Pacific they occur from southern California to Chili. It will be 
seen from this range that Horny Sponges do not occur wn very cold water and 
