BABNACLES. 201 



sets under water, and the animal is henceforth immov- 

 able. 



It now moults its skin once more. Another great 

 change takes place ; the bivalve shell is thrown off, as are 

 also the eyes with their bent supports, and it is seen to be 

 a true Barnacle, though as yet of minute dimensions, and 

 with its valves in a very rudimentary condition. It is 

 now the representative of a third type among the Crusta- 

 cean forms, for it is in effect a Stomapod ; * such as the 

 Opossum Shrimp (My sis), for example, with the shield 

 composed of several pieces, stony in texture, on account of 

 the great development of their calcareous element, and so 

 modified in form as to make a low cone, the legs (become 

 the cirri, or whafc I have above called the " fingers ") 

 made to perform their movements backwards instead of 

 forwards, and the whole abdomen reduced to an almost 

 invisible point. 



Marvellous indeed are these facts. If such changes as 

 these, or anything approaching to them, took place in the 

 history of some familiar domestic animal, if the horse, 

 for instance, were invariably born under the form of a fish, 

 passed through several modifications of this form, imitating 

 the shape of the perch, then the pike, then the eel, by 

 successive castings of its skin ; then by another shift ap- 

 peared as a bird ; and then, glueing itself by its forehead to 

 some stone, with its feet in the air, threw off its covering 

 once more, and became a foal, which then gradually grew 

 into a horse ; or if some veracious traveller, some Living- 

 stone or Barth, 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 



* From the Greek <rro/xa (stoma), mouth, and irovs (pous), foot. A 

 name given to those Crustaceans which have proper feet near the 

 mouth. 



