390 
POPULAK SCIENCE KEYIEW. 
either fixed or movable, they are nevertheless to be distin- | 
guished from the latter group by having their main body 
hanging from a stalk, pedicle, or peduncle, of varying length, 
which permits of some degree of motion, while the body of the ^ 
sessile kinds is directly fixed to its support by a firm and often jf 
broad base.* Both kinds must be fairly familiar even to the ^ 
most ordinary sea-side visitor ; the pedunculated, in the shape I 
of the pink clusters, like locks of a Medusa’s hair, which, 
clinging to a worm-eaten fragment of wreck, or to the cork f 
float of a fisherman’s seine, he sees thrown upon the shore after ; 
a storm ; while the sessile varieties, as little, short, coarsely 
truncated, clustered cones — not limpets — try the tenderness of 
his feet when he takes his bathe from the rocks. 
As regards geographical distribution, these animals extend 
all over the world ; those, of course, attached to floating objects 
having the widest range. These excepted, the majority inhabit 
the warmer temperate and tropical seas. Of those attached 
to fixed objects, or to littoral animals, rarely more than three 
or four species are found in the same locality. Of the pedun- 
culated kinds, the fixed Lepadidw — to which family the com- 
mon ship-barnacle belongs — are attached mostly to organic - 
bodies, some being deeply embedded in the skin of the shark 
{Anelasma squalicola) or of whales {Goronula hcdoenaris)^ 
while others fasten upon turtles, sponges, various molluscs, or • 
, inhabit the gill-cavities of Crustaceans (as Dichelaspis in a 
Palinurus). 
1 have before me, as I write, some specimens of Spirula 
shells, and of the lovely lilac lanthina, which floats in mid- 
ocean, buoyed up by its egg-raft, to which certain Lepadidce 
are adhering ; also of a crab from China waters (fig. 4), i 
on either side of whose carapace Conchoderma Hunteri has ! 
effected a lodgment. | With regard to the geographical range ' | 
of sessile Cirripedes, they are found in every sea, from lat. 74^^ 
18' North to Cape Horn ; but their distribution is much affected 
by locality, as they do not live upon coral reefs, or where shores 
and sea bottoms are muddy, sandy, or are formed of shifting 
shingle. 
With regard to fossil Cirripedia, geologists have had much 
difficulty in identifying specimens, because the shell-valves of 
the same species are rarely co-embedded, since the membrane 
* A parallel nomenclature will at once occur to tlie l)otanist as applied to 
the two varieties of oak which inhabit this country. 
f These specimens, presented to the University Museum, Oxford, by 
Robert Garner, Esq., F.L.S., were kindly lent to me by my former teacher, ^ 
Professor Rolleston, E.R.S. 
