402 Dr. F. Miller on Balanus armatus. 
tirely wanting. The maaille have a straight margin, with 
a very minute notch below the uppermost sete, or with- 
out any such notch. There is no projection for the lower 
bristles. The upper and the two lowest sete are only a little 
longer than the longest of the middle ones. Only about one- 
third of the upper margin of the maxille is hairy. 
Cirrt.—F ist pair: the longer branch is about twice as long 
as the shorter one, sometimes still longer, and has twice as 
many joints (eighteen to twenty) ; the last joints are consider- 
ably longer than the lower ones, cylindrical, and beset at the 
end with an almost complete circlet of sete. The shorter 
branch has usually from nine to eleven short joints, with 
densely setiferous processes on the bowed side, most consider- 
able on the middle joints. 
Second pair short, stout, densely bristled; the anterior or 
outer branch with from eleven to thirteen joints, only about 
one-fifth or one-fourth longer than the inner one; the fatter is 
9-10-jointed, and about as long as the shorter branch of the 
first pair. In cast skins, and also usually in other cases, the 
longer branch is seen straightly extended, and the shorter one 
slightly curved. 
Third pair: from the base of this pair of feet a line densely 
beset with long thin hairs runs upwards towards the back. 
In length and form this pair hold a middle place between the 
short and stout cirri of the preceding and the long slender 
cirri of the following pairs. ‘The slightly longer anterior or 
outer branch has about fifteen to seventeen joints, the hinder 
branch one or two fewer. The branches are about as long as 
the longer branch of the first pair. A larger or smaller num- 
ber of the joints of both branches are armed on the curved 
side with strong curved teeth: in young animals the armature 
is weaker and confined to some of the middle joints; in the 
larger animals, only the last two joints of the outer and the 
last four or five joints of the inner branch usually want the 
teeth. The armature of the outer branch is always stronger 
than that of the inner one. These hooked decurved teeth 
(fig. 21) not only occupy the ney part of the strongly pro- 
minent margin of the flexed side of the joints, but extend 
thence, gradually becoming smaller, and finally converted 
into mere minute points over a larger or smaller part of the 
outer surface of the joints. This portion which is beset with 
teeth and hooks is usually elevated, in the form of a low swel- 
ling, a little above the surrounding parts. Besides the teeth of 
the flexed side, there are, especially on the lower joints, acute 
spinules directed upwards on the extended side, a few spines 
also directed upwards, on the outside of the upper margin, an 
