Journal Article Polyp Hypertrophy as an Expression of Aging in the Colonial Marine Hydroid Hydractinia echinata Get access Steven E. Toth, B.S. Steven E. Toth, B.S. 3Marine Biology Laboratory, Department Of Biology, Bowling Green State UniversityBowling Green, Ohio. Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Gerontology, Volume 21, Issue 2, April 1966, Pages 221–229, https://doi.org/10.1093/geronj/21.2.221 Published: 01 April 1966