32 
Guide to Crustacea . 
Order 1. — Thoracica. 
Table-case This Order includes the typical Cirripedes, in which the six 
pairs of feathery trunk-limbs are well developed. Two sub-orders 
are recognised. 
In the sub-order Pedunculata (the Stalked Barnacles) there 
is a fleshy peduncle, or stalk of attachment, at the free end of 
which is the “ capitulum ” formed by the mantle enclosing the 
body and limbs. 
Specimens of the common Goose-Barnacle, Lepas anatifcra 
(Fig. 12), are exhibited showing the external appearance with the 
A. A stalked Barnacle ( Lepas anatifera). B. A sessile Barnacle ( Balanus 
hameri). p., The peduncle. The other letters relate to the “valves” or 
parts of the shell; c., carina; c.l., carino-lateral ; l., lateral; r. + r.l., 
rostrum and rostro-lateral fused together ; sc., scutum ; t., tergum. 
(From Lankester’s “ Treatise on Zoology,” after Darwin.) 
feathery “cirri” extended from the opening of the shell; in 
another specimen half of the shell is removed to show the form of 
the body and limbs within it ; and a third preparation shows the 
five valves of the shell (Fig. 13a) separated from each other. Like 
many other barnacles, the species of Lepas are commonly attached 
to floating objects, drift-wood, ships’ bottoms, and the like, and 
most of the species have an extremely wide distribution in all the 
oceans. The great length sometimes reached by the peduncle of 
the common goose -barnacle is shown by a fine group of specimens 
mounted in a jar by the doorway at the south end of the gallery. 
Among the other genera of stalked barnacles exhibited, Polli- 
