Crustaceans 91 



study since its extreme transparency 

 permits a clear view of all its internal 

 organs. Apart from the zoologist few 

 appreciate the fact that the familiar 

 barnacle is a close relation of the crabs 

 and lobsters. Up till the early nine- 

 teenth century, when the larval stages 

 were first made known, it was classed 

 as a mollusc. We now know that the 

 newly-born barnacle is a free swimming 

 animal with a typical crustacean physi- 

 ognomy, with three pairs of legs and a 

 conspicuous third or median eye. After 

 a time it attaches itself by the head end 

 provided for the purpose with a special 

 cement to a rock or other solid object 

 and acquires the stout armour character- 

 istic of the adult. Certain species attach 

 themselves to living crabs or lobsters, 

 others to molluscan shells, and a few 

 even to living whales and turtles. 



The Goose Barnacles, so-called from 

 the ancient belief that they turned into 



