354 THE INHABITANTS OF THE SEA. 
and large clusters of barnacles appeared, which, having no 
doubt devoured the soft parts of the Velelle, now invested their 
horny skeletons. As the ship advanced, the number of the 
barnacle clusters augmented, which, to judge from the various 
sizes of the individuals, must have taken some time for their 
formation, and were apparently destined to increase until the 
final destruction of the Velellz hosts, into which, from their 
greater weight, they were continually drifting deeper and 
deeper by the action of the currents. Again two or three days 
elapsed, and as the surface of the sea occupied by both species 
of animals extended at the least over four degrees of latitude, 
Velella spirans, somewhat enlarged. 
b. One of its smaller polypites, much magnified. v. Crest. A. Liver. o. Mouth of polypite, 
6. Its diges ive cavity. ¢’. Rounded elevations, containing thread-cells. g. Medusiform zodids. 
a faint idea may be formed of their numbers. Shoals of 
dolphins and sperm-whales were busy exterminating the bar- 
nacles, as these had devoured the Velelle. The whole scene 
was an example on the grandest seale of the destruction and 
regeneration perpetually going on in the wastes of the ocean. 
The Physaliz, which far surpass the Velelle in size and 
beauty, are also inhabitants of the warmer seas, where the Phy- 
salia caravella, or ‘* Portuguese man-of-war,” is the mariner’s 
admiration. On a large float-bladder eight or nine inches long 
and three inches broad, whose transparent crystal shines in every 
