INTRODUCTION. 



Cirripedia may be divided, as I have recently shown in a monograph on the Balanidse 

 published by the Ray Society, into three Orders : of these, the Thoracica includes all 

 ordinary Cirripedes, and all ever likely to be found fossil, and therefore the two other orders 

 may be here passed over without notice. The Thoracica contains three Families : the 

 Balanidse or Sessile Cirripedes, which in a recent state so abound on the shores of almost 

 every quarter of the world, and which are so frequently found in Tertiary deposits ; the 

 Verrucidse, which includes only a single genus very singular from its asymmetrical 

 shell ; and the Lepadidse, or Pedunculated Cirripedes ; of the latter, the Fossil species have 

 been already published by the Paleeontographical Society. The Balanidse and Verrucidge will 

 be treated of in the following pages. As yet only sixteen species in these two families 

 have been found fossil in Great Britain ; and of these sixteen, nine are still living forms. 

 As the latter are known only imperfectly in their fossil condition, and as they have lately 

 been described by me in full detail, I have thought it best here only to make a few remarks 

 on such portions of the shells of each species as have hitherto been discovered, adding a 

 few illustrations, such as appeared to me desirable. The extinct species will be fully 

 described : of these, all the figures given are from British specimens. But of the species 

 found both living and fossil, I have in several instances (always so stated) given drawings 

 from recent specimens ; some of the valves either not having been found fossil, or 

 found only in an imperfect and not characteristic condition. As so few species in the 

 several genera are known in a fossil condition, I have thought it quite superfluous to give 

 long generic descriptions, which would have required constant references to many species 

 exclusively found living. 



In my former monograph on the Fossil Lepadidse, I remarked how much the natural 



1 



