68 HOUSE, GARDEN, AND FIELD 



specimens, and put them into a shallow vessel of sea- 

 water. A week later he found that two of them had cast 

 their skin and were now firmly adhering to the bottom of 

 the vessel. Great was his surprise to find that these 

 adhering forms were young barnacles with conical shells 

 of six ridges, four valves and protruded legs. Other indi- 

 viduals were seen in the act of casting their bivalve shells 

 and attaching themselves to the bottom. The earlier 

 stage, which by a rapid transformation passes into a 

 barnacle, bears jail the marks of an ordinary crustacean, 

 and even its bivalve shell is very like that of a water- 

 flea (see p. r7o). Thompson had now no difficulty in 

 drawing two conclusions ; the barnacles are true crusta- 

 ceans, and they undergo an extraordinary transformation. 



Some further account of the naturalist who first un- 

 ravelled the life-history of the rock-barnacle will, I think, 

 be of interest to my readers, especially as his name is still 

 unknown except to professed zoologists. One proof of this 

 is that he was not included in the first list of Englishmen 

 deemed worthy of mention in the Dictionary of National 

 Biography. Happily for the credit of the dictionary, and 

 we may even say for the credit of Englishmen, the omis- 

 sion was repaired in time, and an excellent notice by Dr. 

 F. W. Gamble tells the story of a naturalist who will be 

 remembered when a thousand celebrities of his own day 

 are forgotten. 



John Vaughan Thompson (1779-1847) was an army- 

 surgeon, who served his country during the great French 

 war, being stationed by turns in the West Indies, Mada- 

 gascar and the Mauritius. After the peace he was trans- 

 ferred to Cork, where his most notable zoological work 

 was done and published. His last years, occupied chiefly 

 with medical duties, were spent in Sydney, where he died. 

 Thompson has written his name indelibly in the history 

 of zoology by the following capital discoveries : (i) The 

 development of the land-crab of the West Indies, and the 

 proof that the spawning and early development take place 



