Vice-Preside'nfs Address. 283 



Such animals Professor Cleland very appropriately desig- 

 nates as "terminal forms of life." Among a number of 

 examples of this class quoted by him, I shall only mention 

 the Lampshells (Brachiopoda), a genus of which gives name 

 to the Liugula Flags of the Cambrian period. "By what 

 means," writes Professor Cleland, " the Lingula arose — with 

 whatever ancestry — it had completed its development in 

 those far-off days, long before the earliest trace of a verte- 

 brate; and, after having completed its development, there 

 it has remained, closing its valves through the long ages 

 against all the changes in the outer world in that tremendous 

 lapse of years which separates the deposit of the Lingula 

 Flags from our own day. Surely to such a persistent genus 

 as this we may fairly give the title of a terminal form" 

 (Journal of Anatomy and Physiology, vol. viii. p. 350). 



The same remarks apply to many of the Protozoa of the 

 present day, especially unicellular organisms, some of which 

 would be, probably, undistinguishable from their predecessors 

 in all ages, had we the means of making a comparison 

 between them. This idea is so far borne out by the organ- 

 isms recently dredged up from the bed of the Atlantic, 

 such as Foraminifera, Sponges, Corals, etc., many of which 

 have been declared to be similar to analogous forms in 

 chalk. On the other hand, at a much later period than the 

 Cambrian, many genera and species had arisen, flourished 

 for a time, and then vanished for ever. Such were the 

 Ichthyosaurus, the Flcsiosaurus, the Pterodactyle, and many 

 other strange forms of swimming and flying reptiles, which 

 became extinct towards the end of the Cretaceous period. 

 The study of the life-history of these extinct animals is 

 most fascinating to all lovers of the marvellous, and most 

 instructive to the evolutionist. 



Although many of the higher animals which had a wide 

 range in the Tertiary period have also become extinct as 

 species, yet their direct but greatly modified represen- 

 tatives are at the present time probably more numerous 

 than at any former period. Apparently, the modifying 

 influences have told upon them more quickly, so that trans- 

 formations of considerable extent have been effected in a 



