350 PALAEONTOLOGY OF NEW YORK. 



Finality , it is important to emphasize the intimate similarity between Rensse- 

 LAERiA and the pentameroid genus Amphigenia ; genera in which the essential 

 distinction between the typical forms of each lies in the simple loop of the 

 former and the long, expanded but still discrete crural processes of the latter. 

 Attention has been directed to these similarities and differences, and it has also 

 been pointed out that the spondylium in Amphigenia elongaia is at times almost 

 reproduced in specimens of Rensselaeria ovoides where the dental lamellae are 

 highly developed. 



