The President's Address. By Henry Woodward. 145 



"While upon the subject of the evolution and extinction of life- 

 forms I may be permitted to refer you to a very able paper which 

 lias lately appeared,* by Mr. C. B. Crampton, on this subject. 



To-night I will only venture to glance at some of the Inverte- 

 brata; leaving the Vertebrata to be discussed upon another 

 ■occasion. 



" In the first place (Mr. Crampton writes) the lowly-organised 

 groups have persisted in spite of the gradual evolution of more and 

 more highly-organised forms, and this must be due in large measure 

 to their rapid growth and reproductive powers. 



(2) That groups appear to have a shorter range in time as they 

 acquire a higher degree of organisation. 



(3) That living forms of groups that are dominant at the 

 present time rarely show ancestors of such great specialisation as 

 themselves. 



(4) That forms that are now isolated in their zoological affini- 

 ties, and bordering on extinction, are generally highly specialised 

 in some direction, but often show signs of degeneration, and usually 

 have ancestors of greater specialisation during some former period 

 of dominance. A few, at any rate, seem to show a smaller degree 

 of fertility than might be expected. 



(5) Other forms which have come down to us from a distant 

 period with small amount of change, or with very gradually- 

 acquired specialisation, often show a great power of resistance to 

 death. They are also generally extremely fertile. 



(6) That extinct groups seem almost invariably to have 

 ■acquired a great degree of specialisation during their period of 

 dominance. 



(7) That the more specialised genera and species of groups 

 tend to have a shorter range in time than the less specialised, 

 although they frequently appear to have temporarily acquired a 

 greater dominance. 



(8) When a group shows very quickly-acquired variation and 

 specialisation its range is usually very restricted. 



(9) That the later forms in extinct groups frequently show 

 signs of degeneration, and sometimes a more primitive organisation 

 than the most specialised forms, possibly owing their persistence 

 to their slower specialisation. 



(10) That long retention of primitive characteristics, or a great 

 degree of stability and want of variation, has been usually asso- 

 ciated with a long range in time. 



(11) That higher groups do not spring from the most specialised 

 forms of the parent groups before them in time, but from some 

 generalised form in those groups which had retained a more primi- 

 tive organisation." 



• Proc. Roy. Phys. Soc. Edic., xiv. p. 461 ; read March 20th, 1901. 

 April 15 th, 1903 i< 



