42 THE LIFE OF CRUSTACEA 



long classed by naturalists with the Mollusca. 

 was not until their larval development was made 

 known that they were recognized as Crustacea. 

 The common Goose Barnacle (Lepas anatifera 

 Plate III.) is found adhering to the bottoms of ships 

 and to floating timber. It has a fleshy stalk or 

 peduncle which is fixed at one end to the supporting 

 object, and bears at the other end a shell, made up 

 of five separate plates, enclosing the body of the 

 animal. The stalk corresponds to the front part of 

 the head, and careful examination may discover at 

 its end, among the hardened cement which fixes it 

 to the support, the remains of the antennules by 

 which the attachment of the young animal was first 

 effected. The body of the animal within the cara- 

 pace or shell bears the usual mandibles, maxillulae, 

 and maxillae, close to the mouth, and six pairs of 

 long, tendril-like feet. These feet have each two 

 branches, composed of numerous short segments 

 and fringed with long hairs. They can be protruded 

 from'the slit-like opening of the shell, forming a sort 

 of " casting-net " for the capture of minute floating 

 prey. 



The Acorn-shells, of which one species (Balanus 

 balanoides Plate III.) is abundant everywhere on 

 our coasts, covering rocks and stones just below 

 high-water mark, differ from Lepas and its allies in 

 having no peduncle. The shell is cemented directly 

 to the rock, and is conical in shape, like a small 



