SUPPLEMENT 
ON THE 
SIXTH CLASS OF THE MOLLUSCA. 
THE CIRROPODA. 
THE ANATIFA is a genus distinguished, as well as the 
Balani, from all the other animals of this division, by articu- 
lated and ciliated tentacula, ranged by pairs, to the number of 
twenty or more, on each side of their body. ‘They were the 
more deserving of forming a separate order, or class, as they 
now stand, inasmuch as they approximate in many respects 
to the articulated animals. 
The name of anatifa is an abridgment of anatifera, and 
owes its origin to a strange fable. Believing some analogy 
to exist between the most extended species of the anatifa, 
and the numerous wild ducks, or bernacles, which abound on 
the maritime shores of the west and north of Europe, their 
inhabitants imagined that it gave birth to these birds, and it 
therefore received the name of anatifera, or bernacle. 
The shell of the anatifera has the form of a flatted cone. 
It is usually composed of five or seven principal valves, and 
sometimes of a great number of small ones, for the most part 
triangular, or trapezoid. These valves are not joined by 
means of any hinge. ‘They hold together by means of the 
