|Annu. Rev. Astron. Astrophys. 1984. 22:
Copyright © 1984 by . All rights reserved
Cluster cores are the sites where perhaps the most severe environment-related alterations to the evolution of galaxies occur. The question has been frequently asked, To what extent is the morphological type segregation, observed to be dependent on the galaxian density, the result of these alterations? In broad terms, this question is reviewed by Dressler (33) in this volume. Here, we consider the evidence that has accumulated from H I observations in favor of the effectiveness of mechanisms that dramatically affect the structure of spiral disks.