94 GUIDE TO THE FOSSIL INVERTEBRATE ANIMALS. 
Gallery 
VIII. 
Table-case 
22 . 
Wall-case 
13b, c. 
Tile CIRRIPEDIA, or barnacles and their allies, are of 
special interest to Ilritish naturalists as having formed the 
subject of two monographs, on the recent and fossil forms 
respectively, by Charles Darwin. They have a wider 
interest as representatives of a free and actively moving 
group of animals that, so soon as their early wandering days 
are over, settle down to a fixed existence, becoming perma- 
nently attached by the forepart of the head to rocks, shells, 
drift-wood, ships, and the like. Some, as the common 
Fig. 4G. — Fossil Crustacea, i, a Bracliyuran Decapod of the tribe Dro- 
miacea, DromilUes Lamarchi, London Claj'. 2, a Brachyuran Decapod 
of the tribe Oxystomata, Palmocoiijstes Stokesi, Gault and Upper 
Greensand. 3, a Macruran Decapod of the tribe Eryonidea, Eryon 
arctiformis, Solenhofen Stone. 4, a ]\Iacruran Decapod of the tribe 
Loricata, Mecochirus longimamis, Solenhofen Stone. 5, an Ostracod, 
Cypridca tubcrculata, Wealden. 6, a Cirripede, Loricula pulchella, 
Turonian Chalk ; the specimen was figured by C. Darwin. All figures 
except 5 and 6 are considerably less than natural size. 
Balani or acorn-shells of our coasts, are closely and imme- 
diately attached to the rock or wood ; others, as the barnacles, 
hang from a long stalk. In either case they develop a 
calcified shell composed of a number of definite pieces. 
Six pairs of feathery cirrus-like limb.s, to which the Sub- 
Class owes its name, stretch out from the shell, and con- 
tinuou.sly sweep food -particles to the mouth within the shell. 
In the Ordovician, Silurian, and Devonian rocks occur 
fossils like tubes of overlapping scales, supposed to have 
been the plated covering of primitive cirripedes in wliich 
the main shell or capitulum was not yet distinguished from 
the covering of the stalk ; such are Lcpidocoleus, with two 
