646 THE GOOSE-MUSSEL OR DUCK-BARNACLE. 



when applied to the water wherein a number of these tiny creatures are swimming 

 discloses a swarm of merry little beings playing about just like the clouds of gnats over 

 water, or the dancing motes in the sunbeam. 



Just in the middle of the part of the body which by courtesy we will call the fore- 

 head, a single eye is placed, black, round, and shining as if it were a little jet bead in- 

 serted into the body. There are also two very large antennae, which serve two useful 

 purposes, for they aid the free and imperfect Barnacles to proceed through the water, 

 while they are the means whereby the creature fixes itself to the rock when about to 

 undergo its last change. 



It then passes through a series of changes, casting off its skin at every change, and 

 exhibiting the curious phenomenon that, in its form and general appearance, it presents 

 a strange resemblance to the young of several Entomostraca, such as cypris and cyclops. 

 When it is ready for the final change, the young Barnacle seeks some rock or other 

 resting-place, and begins operations by pressing the large antennae against the sup- 

 porting substance. A curious cement or glue is then poured from their bases : as this 

 cement is not soluble in water, it fixes the creature firmly to the rock. Almost as soon 

 as it is fairly settled, the Barnacle again casts its skin, parting with the bivalve shell 

 which guarded its body, casting away the eye which has hitherto directed its course, 

 and assumes, though still of very minute form, the shape of the adult. 



After describing these wonderful changes, Mr. Gosse makes the following apt 

 remark. " Marvellous indeed are these facts. If such changes as these or anything 

 like them, took place in the history of some familiar domestic animal if the horse, for 

 instance, were invariably born under the shape of a fish, passed through several 

 modifications of this form, imitating the shape of the perch, then the pike, then the eel, 

 by successive casting off its skin ; then by another shift appeared as a bird, and then, 

 gluing itself by its forehead to some stone, with its feet in the air, threw off its cover- 

 ing once more and became a foal, which then gradually grew into a horse ; -or if some 

 veracious traveller, some Livingstone or Earth, were to tell us that such processes were 

 the invariable conditions under which some beast of burden largely used in the centre 

 of Africa passed ; should we not think them very wonderful ? Yet they would not be 

 a whit more wonderful in this supposed case than in the case of the Barnacle, in 

 whose history they are constantly exhibited in millions of individuals and have been 

 for ages and even in creatures so common that we cannot take a walk beneath our 

 sea cliffs without treading on them by hundreds." 



Having thus glanced cursorily at the general structure and habits of the cirrhi- 

 pedes, we will proceed to the individual specimens which are figured in the illus- 

 tration. 



Ix the upper left-hand corner of the illustration is seen a group of the common 

 GOOSE-MUSSEL or DUCK-BARNACLE, so called on account of the absurd idea that was 

 once so widely entertained, that this species of barnacle was the preliminary state of 

 the barnacle-goose, the cirrhi representing the plumage, and the valves doing duty for 

 the wings. 



This Barnacle is tolerably universal in its tastes. It clings to anything, whether still 

 or moving, and is the pest of ships on account of the pertinacity with which it adheres 

 to their planks. Its growth is marvellously rapid, and in a very short time a vessel 

 will have the whole of the submerged surface coated so thickly with these cirrhipedes 

 -that her rate of speed is sadly diminished by the friction of their loose bodies against 

 the water. 



When once the Goose-mussel has affixed itself to any object, the rapidity of its 

 growth is positively startling. The minute young are poured from its shells in such 

 multitudes that they look like cloudy currents in the water ; and after they have en- 

 joyed their brief period of freedom, they settle down, attain maturity, and in their turn 

 become the origin of a countless posterity. 



I have seen a large log of timber, about fourteen feet in length by one foot square, 

 so thickly covered with these Barnacles that the wood on which they rested was not 

 visible. The same log, which had evidently formed part of the cargo of a timber ship, 



