ON THE GENUS URASTERELLA WITH DESCRIPTION 

 OF A NEW SPECIES 



BY GEORGE HENJRY HUDSON 



Many fossil forms are imperfectly understood because of lack 

 of complete and accurate descriptions of material already preserved 

 in museums. The type of study that should be given such is well 

 exemplified in Bather's " Studies in Edrioasteroidea " appearing in 

 the Geological Magazine at various dates from 1898 to 191 5 inclu- 

 sive and now privately published (October 1915) by the author at 

 " Fabo," Marryat Road, Wimbledon, England. The writer of the 

 present paper has endeavored to pattern after so good an example 

 and he hopes that the more intensive study given to three American 

 specimens of Urasterella has revealed much that is new and of 

 profound import. 



Bather's studies also emphasize a second need, and that is for 

 more material. Collectors must come to realize that perfect speci- 

 mens are by no means the only ones desired. Well-weathered 

 fragments may often reveal anatomical detail not heretofore sus- 

 pected and any fragment may prove of great value if used as 

 material for sectioning. Certain collectors, after examining some 

 indication of " a find " often decide that the fragment is worthless 

 as a cabinet specimen and many times it receives a parting blow, 

 thoughtlessly given with the face of the hammer. This condition 

 of things is not imaginary and in certain choice hunting grounds 

 has doubtless led to serious loss. In many localities all weathered 

 surfaces have been fairly well stripped. The value of, and desire 

 for, fragments of rare forms should be made widely known. 



The studies to be presented here will illustrate also another 

 hinderance to understanding, and that is that our systems of classi- 

 fication and group definitions in many cases serve to cloud our 

 vision and not only lead us to insist on the presence of structures 

 where they do not exist but also to deny the reality of structures 

 truly present. For instance, the idea that species of Uras- 

 terella were asteroids has led students and authors for over 

 fifty years to give them arm cavities containing ampullae and double 

 rows of podial openings through the floors of their food grooves. 

 Even so keen and experienced an observer as Schuchert (191 5) 

 has both specified and illustrated podial openings for this genus. 



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