EXTENSIONS OF DARWINISM 



289 



periods of the Mesozoic age, till towards llie end, when the 

 whole race was about to die out, they seemed to try to go 

 back to their original form, which some almost reached (Fi^. 



Fig. 99. — Ceratites nodosus. 

 Trias. 



Fig. 100. — Trachyceras aon. 

 Trias. 



105), while others, as Professor Judd remarks (in a letter), 

 " before finally disappearing, twisted and untwisted them- 

 selves, and as it were wriggled themselves into extraordinary 



Fig. 101. — Crioceras emerici. 

 Cretaceous. 



Fig. 102. — Ileteroceras cmcrici. 

 Cretaceous. 



shapes, in the last throes of dissolution.'- These strange forms 

 (Figs. 90-106) are reproduced from Nicholson's PaUeontol- 

 ogy, and there are many others. 



