ON CIRROPODA. 431 
laminz, of which the furrows, canaliculations or striz, are 
usually in a direction opposite to those of the first. They hold 
together by the teeth of their edge, which are fastened one in 
the other, or by a scaly suture. Their structure is sometimes 
tubular, and very remarkable. ‘They rest, in the greater num- 
ber of species, on a base of the same nature, more or less 
thick, flatted, or hollowed, which holds strongly to the bodies 
on which the animal has the habit of fixing. This base is of 
a coriaceous nature in a small number; sometimes it appears 
to be wanting altogether. Finally, an operculum, usually 
pyramidal, and formed of two or four valves, closes the 
superior aperture. It is raised, or lowered, by five different 
muscles, and holds to the valves by a tendinous membrane, 
ample enough to permit the play of the muscles. The form 
of the valves, that of the operculum, and of the base itself, 
vary in the different species. The majority of the balani 
unite, like the anatifee, in groups more or less numerous, in 
which individuals of all sizes are to be met with. Frequently 
this agglomeration does not allow all of them to be equally 
developed, and hinders the sheli from assuming its natural 
figure. The lepas testudinaria, or balanus of the tortoise, 
and that which lives parasitically on the whale, are the only 
species which are isolated. Some of them are to be found in 
all the known seas, and many are extended through very re- 
mote latitudes. ‘Their fecundity is almost beyond what ima- 
gination can conceive. They lay their eggs in summer, and 
the little ones which issue from them are filled at the end of 
four months, according to the observation of Poli, with similar 
eggs ready to disclose. Their manceuvres to draw to them 
their nutriment are the same as those of the anatife. They 
raise their operculum at every moment, put forth their arms, 
move them with great swiftness, and draw them in with equal 
velocity. This is always done on the approach of the 
slightest danger. The ancients were of opinion that they 
