252 MARINE INVERTEBRATES 



shed, and in the spring of the year these thin, glossy casts are found 

 in abundance floating on the surface of the water near the shore. 



There are but three orders of barnacles, namely, those in which 

 the shell is directly attached to the rocks, those which are attached 

 to floating objects by a long stalk, and those which are parasitic 

 on animals. A species of the third order infests the whale. 



The older zoologists classed barnacles with the Molhtsca, but in 

 1829 Vaughan Thompson, in the study of their embryology, 

 found that they should be classed with crustaceans, in company 

 with crabs, shrimps, and water-fleas, with which their immature 

 forms show direct relationship. 



GENUS Lepas 



This genus is commonly known as the ship-barnacle, also as 

 the goose-barnacle. It attaches itself to floating logs as well as 

 to ships, but the latter form its principal home ; consequently it 

 is a great voyager, and, though common everywhere, is every- 

 where considered a stranger. The same species are found on 

 ships coming from the most remote and widely separated regions, 

 and so they cannot be considered native to any one locality. 

 They are wanderers on the deep, and grow in such numbers on 

 the bottoms of ships, especially of those which sail in warm seas, 

 that they seriously impede the progress of the vessels. Aside 

 from diminishing its speed, they do a ship no injury. 



There was a tradition, which lasted several centuries, that geese 

 were hatched from these shells, which somewhat resemble eggs. 

 Gerard, in the appendix to his " Herball or Generale Historic of 

 Plants" (1597), gives a picture of shells of Lepas growing on a 

 tree, with geese falling from them and swimming about in the 

 water below. His description is as follows : " There are founde 

 in the Norldi parts of Scotland and the islands adjacent called 

 Orchades certaine trees whereon do growe certaine shell fishes of a 

 white color, tending to russet, wherein are conteined little living 

 creatures ; which shells in time of maturitie do open, and out of 

 them grow those little living f oules whom we call barnakles, in the 

 North of England brant geise, and in Lancashire tree geise ; but 



