126 NUDIBRANCHIATA.—EOLIDID A. 
moves them irregularly about, they shine with a 
radiance resembling that of rubies and sapphires. 
These elegant branchiz seem very easily dis- 
lodged; the specimens I have kept have usually 
lost one or more tufts, which, however, soon begin 
to sprout again. They are liable to be lost through 
the pugnacity of the animals themselves, as their 
predaceous habits frequently impel them to tear off 
each other’s papille. 
In captivity, this Holis is very active, continu- 
ally gliding with a uniform motion around the 
sides of the vessel, or climbing about the numerous 
branching sea-weeds that are growing in it. They 
frequently crawl close to the edge of the water, but 
never come actually out, though they occasionally 
float at the surface, by means of the expanded foot, 
back downwards. 
Another species (Z. punctata) has been heard to 
make that peculiar clicking sound, already men- 
tioned as produced by Tritonia. 
