One of the more common echinoids in the Cretaceous of Texas is Heteraster texanus. Here is a specimen that I got from Dan Woehr who does a terrific write up of his collecting excursions at "Meanderings of a Texas Fossil Hunter".
Adapical surface (top)
Adoral surface (underside or bottom)
This specimen is from the Walnut formation (Albian stage of the Cretaceous) of Bell County, Texas. than to Dan for sending me this fossil.