UINTACRINUS: ITS STRUCTURE AND RELATIONS. 13 



The drawings for the illustration of the following pages were made by 

 Mr. K. M. Chapman, teacher of art in the New Mexico Normal University 

 at Las Vegas, and Mrs. E. Ricker, of Burlington, Iowa. It is a pleasure to 

 acknowledge the zeal and intelligent interest with which they have labored 

 to meet my wishes. The photographs were mostly made by Mr. Maurice 

 Ricker, Principal of the Burlington High School, whose high scientific attain- 

 ments and accurate methods, added to great skill with the camera, enabled 

 him to afford me much valuable assistance. 



