REV. T. RIDDBLI. ON THE BALANU8. 



195 



Mean barometric height at the le- ) . 



, } l 



vel of the sea = 29 82 inches 



, ,-,. 

 1>4 ' 45 



Log. 29.286 =1.4667 



.0078 



1000.0. 



Height of the place of observation must be 

 somewhere about 



78 fathoms, or 468 ft. 



On the Metamorphosis of the Balanus punctatus of Montagu. By the 

 Rev. T. RIDDELL, Fellow of Trinity College, Cambridge. 



Among all the facts recently brought to light in Animal History, 

 there is, perhaps, none more wonderful than the discovery made by Mr 

 Vaughan Thompson, and published in his Zoological Researches, re- 

 specting the transformation of the Balani. An account of Mr T.'s ob- 

 servations, together with a statement of the opinions of several eminent 

 naturalists respecting the correctness of his views, may be found in the 

 Penny Cyclopaedia, Art. CIRRIPEOA. That an animal should be fur- 

 nished, in the first stage of its existence, with organs of motion and 

 s\\im about freely like a shrimp, and afterwards became immoveably 

 fixed to a rock and clothed with a hard stony shell, seems at first sight 

 so highly improbable, that persons might be expected to suspend their be- 

 lief till the fact should be fully proved. 



Having heard from Dr Johnston in the beginning of June that he had 

 found Balani in all their stages, near the mouth of the river at the fishing 

 bat opposite Spitt.il, I went down the first favourable day to the place 

 he had mentioned, and succeeded in obtaining several of the animals in 

 the earliest stage of their growth, as described by Mr Thompson. They 

 were spread in countless numbers over the stones, but none of them 

 were free ; all were found adhering, seemingly by a short fine pedicle or 

 talk, to some object, either stone, shell, or sea-weed. In the course of 



B. N. c. NO. viu. p 



