Simple invertebrate metazoa offer many potentialities for study of growth and differentiation - potentialities which have not been realized because the organisms usually have been difficult to handle in the laboratory. A simple coelenterate, the brackish-water colonial hydroid Cordylophora lacustris, was selected for the present work, and was domesticated so that it could be grown and manipulated under controlled laboratory conditions. Methods have been developed permitting exponential increase in hydranth number with a doubling time of about three days. Five ions — Na+, K+, Ca++, Mg++, Cl- — have been found to be required for growth in the defined aqueous environment, and other variables influencing growth rate have been systematically studied. The colonies are fed daily with living larvae of the brine shrimp, Artemia. The control of the feeding reaction has been studied. It has been found that, as in Hydra (Loomis, 1955), a single molecular species released from captured prey induces the feeding reaction. The active compound has been isolated from Artemia extract and identified as the imino acid proline, and reagent proline has been found to induce the feeding reaction at 10-5 molar. Magnesium, and possibly phosphate ions, have been shown to influence the response to proline. Perhaps the most interesting aspect of this discovery is from the point of view of comparative biochemistry and evolution, for previous workers have found that the feeding reactions of three other Hydrozoa are controlled by reduced glutathione. Time-lapse cinematography of the colonies has revealed proximally-oriented peristaltic waves which apparently act to circulate nutrients through the colonies. These waves are rhythmic, and occur about once every twenty-five minutes in resting colonies. After feeding, the frequency of the waves increases to one every eight minutes, and falls back to the resting rate over the course of several hours. The most striking feature of the peristalsis is that it is synchronized throughout a colony, in that the waves begin at the tip of each hydranth simultaneously. The time-lapse movies have also elucidated a series of rhythmic movements which occur during the reconstitution of hydranths from tissue fragments. The major emphasis of the study has been an attempt to gain an understanding of the asexual development of a Cordylophora colony. While at first glance a colony appears to be a forest of little trees, on closer examination one finds that a colony may be considered a series of tubes of uniform diameter. The shape of a colony may be considered to result from the (1) relative rates of growth, (2) spacing, and (3) angles of these tubes. A descriptive study of the development of shape under one set of culture conditions has been made. On the basis of the three parameters, three types of tubes may be distinguished: stolon tubes, upright tubes, and branch tubes. These tubes were all found to grow at constant, but different rates. This linear growth of tubes posed a paradox, since the number of hydranths in a colony had been found to increase exponentially. It was shown that the dry weight of a colony also increases exponentially, and a model was developed permitting the resolution of linear growth of parts into exponential growth of the whole. Study of the development of individual colonies using a marking technique showed that the development of shape in these colonies proceeded essentially as predicted by the model.
","abstract_html":"<p>Simple invertebrate metazoa offer many potentialities for study of growth and differentiation - potentialities which have not been realized because the organisms usually have been difficult to handle in the laboratory. A simple coelenterate, the brackish-water colonial hydroid Cordylophora lacustris, was selected for the present work, and was domesticated so that it could be grown and manipulated under controlled laboratory conditions. Methods have been developed permitting exponential increase in hydranth number with a doubling time of about three days. Five ions — Na<sup>+</sup>, K<sup>+</sup>, Ca<sup>++</sup>, Mg<sup>++</sup>, Cl<sup>-</sup> — have been found to be required for growth in the defined aqueous environment, and other variables influencing growth rate have been systematically studied. The colonies are fed daily with living larvae of the brine shrimp, Artemia. The control of the feeding reaction has been studied. It has been found that, as in Hydra (Loomis, 1955), a single molecular species released from captured prey induces the feeding reaction. The active compound has been isolated from Artemia extract and identified as the imino acid proline, and reagent proline has been found to induce the feeding reaction at 10<sup>-5</sup> molar. Magnesium, and possibly phosphate ions, have been shown to influence the response to proline. Perhaps the most interesting aspect of this discovery is from the point of view of comparative biochemistry and evolution, for previous workers have found that the feeding reactions of three other Hydrozoa are controlled by reduced glutathione. Time-lapse cinematography of the colonies has revealed proximally-oriented peristaltic waves which apparently act to circulate nutrients through the colonies. These waves are rhythmic, and occur about once every twenty-five minutes in resting colonies. After feeding, the frequency of the waves increases to one every eight minutes, and falls back to the resting rate over the course of several hours. The most striking feature of the peristalsis is that it is synchronized throughout a colony, in that the waves begin at the tip of each hydranth simultaneously. The time-lapse movies have also elucidated a series of rhythmic movements which occur during the reconstitution of hydranths from tissue fragments. The major emphasis of the study has been an attempt to gain an understanding of the asexual development of a Cordylophora colony. While at first glance a colony appears to be a forest of little trees, on closer examination one finds that a colony may be considered a series of tubes of uniform diameter. The shape of a colony may be considered to result from the (1) relative rates of growth, (2) spacing, and (3) angles of these tubes. A descriptive study of the development of shape under one set of culture conditions has been made. On the basis of the three parameters, three types of tubes may be distinguished: stolon tubes, upright tubes, and branch tubes. These tubes were all found to grow at constant, but different rates. This linear growth of tubes posed a paradox, since the number of hydranths in a colony had been found to increase exponentially. It was shown that the dry weight of a colony also increases exponentially, and a model was developed permitting the resolution of linear growth of parts into exponential growth of the whole. Study of the development of individual colonies using a marking technique showed that the development of shape in these colonies proceeded essentially as predicted by the model.</p>","abstract_has_math":false,"creators":["Fulton, Chandler Montgomery"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Norton Zinder"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1960,"date_issued":"1960-01-01T08:00:00Z","date_published":"1960-01-01T08:00:00Z","updated_at":"2026-07-24T04:11:11Z","subjects":["Cordylophora growth","proline feeding","synchronized peristalsis","exponential colony development","Life Sciences"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/209","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Norton Zinder"]},{"key":"dc:creator","label":"Author","values":["Fulton, Chandler Montgomery"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Cordylophora growth","proline feeding","synchronized peristalsis","exponential colony development","Life Sciences"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/209"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Simple invertebrate metazoa offer many potentialities for study of growth and differentiation - potentialities which have not been realized because the organisms usually have been difficult to handle in the laboratory. A simple coelenterate, the brackish-water colonial hydroid Cordylophora lacustris, was selected for the present work, and was domesticated so that it could be grown and manipulated under controlled laboratory conditions. Methods have been developed permitting exponential increase in hydranth number with a doubling time of about three days. Five ions — Na+, K+, Ca++, Mg++, Cl- — have been found to be required for growth in the defined aqueous environment, and other variables influencing growth rate have been systematically studied. The colonies are fed daily with living larvae of the brine shrimp, Artemia. The control of the feeding reaction has been studied. It has been found that, as in Hydra (Loomis, 1955), a single molecular species released from captured prey induces the feeding reaction. The active compound has been isolated from Artemia extract and identified as the imino acid proline, and reagent proline has been found to induce the feeding reaction at 10-5 molar. Magnesium, and possibly phosphate ions, have been shown to influence the response to proline. Perhaps the most interesting aspect of this discovery is from the point of view of comparative biochemistry and evolution, for previous workers have found that the feeding reactions of three other Hydrozoa are controlled by reduced glutathione. Time-lapse cinematography of the colonies has revealed proximally-oriented peristaltic waves which apparently act to circulate nutrients through the colonies. These waves are rhythmic, and occur about once every twenty-five minutes in resting colonies. After feeding, the frequency of the waves increases to one every eight minutes, and falls back to the resting rate over the course of several hours. The most striking feature of the peristalsis is that it is synchronized throughout a colony, in that the waves begin at the tip of each hydranth simultaneously. The time-lapse movies have also elucidated a series of rhythmic movements which occur during the reconstitution of hydranths from tissue fragments. The major emphasis of the study has been an attempt to gain an understanding of the asexual development of a Cordylophora colony. While at first glance a colony appears to be a forest of little trees, on closer examination one finds that a colony may be considered a series of tubes of uniform diameter. The shape of a colony may be considered to result from the (1) relative rates of growth, (2) spacing, and (3) angles of these tubes. A descriptive study of the development of shape under one set of culture conditions has been made. On the basis of the three parameters, three types of tubes may be distinguished: stolon tubes, upright tubes, and branch tubes. These tubes were all found to grow at constant, but different rates. This linear growth of tubes posed a paradox, since the number of hydranths in a colony had been found to increase exponentially. It was shown that the dry weight of a colony also increases exponentially, and a model was developed permitting the resolution of linear growth of parts into exponential growth of the whole. Study of the development of individual colonies using a marking technique showed that the development of shape in these colonies proceeded essentially as predicted by the model.
"]},{"key":"dc:title","label":"Title","values":["The Biology of a Colonial Hydroid"]}]}],"canonical_facts":{"dc:contributor":["Norton Zinder"],"dc:creator":["Fulton, Chandler Montgomery"],"dc:description.abstract":["Simple invertebrate metazoa offer many potentialities for study of growth and differentiation - potentialities which have not been realized because the organisms usually have been difficult to handle in the laboratory. A simple coelenterate, the brackish-water colonial hydroid Cordylophora lacustris, was selected for the present work, and was domesticated so that it could be grown and manipulated under controlled laboratory conditions. Methods have been developed permitting exponential increase in hydranth number with a doubling time of about three days. Five ions — Na+, K+, Ca++, Mg++, Cl- — have been found to be required for growth in the defined aqueous environment, and other variables influencing growth rate have been systematically studied. The colonies are fed daily with living larvae of the brine shrimp, Artemia. The control of the feeding reaction has been studied. It has been found that, as in Hydra (Loomis, 1955), a single molecular species released from captured prey induces the feeding reaction. The active compound has been isolated from Artemia extract and identified as the imino acid proline, and reagent proline has been found to induce the feeding reaction at 10-5 molar. Magnesium, and possibly phosphate ions, have been shown to influence the response to proline. Perhaps the most interesting aspect of this discovery is from the point of view of comparative biochemistry and evolution, for previous workers have found that the feeding reactions of three other Hydrozoa are controlled by reduced glutathione. Time-lapse cinematography of the colonies has revealed proximally-oriented peristaltic waves which apparently act to circulate nutrients through the colonies. These waves are rhythmic, and occur about once every twenty-five minutes in resting colonies. After feeding, the frequency of the waves increases to one every eight minutes, and falls back to the resting rate over the course of several hours. The most striking feature of the peristalsis is that it is synchronized throughout a colony, in that the waves begin at the tip of each hydranth simultaneously. The time-lapse movies have also elucidated a series of rhythmic movements which occur during the reconstitution of hydranths from tissue fragments. The major emphasis of the study has been an attempt to gain an understanding of the asexual development of a Cordylophora colony. While at first glance a colony appears to be a forest of little trees, on closer examination one finds that a colony may be considered a series of tubes of uniform diameter. The shape of a colony may be considered to result from the (1) relative rates of growth, (2) spacing, and (3) angles of these tubes. A descriptive study of the development of shape under one set of culture conditions has been made. On the basis of the three parameters, three types of tubes may be distinguished: stolon tubes, upright tubes, and branch tubes. These tubes were all found to grow at constant, but different rates. This linear growth of tubes posed a paradox, since the number of hydranths in a colony had been found to increase exponentially. It was shown that the dry weight of a colony also increases exponentially, and a model was developed permitting the resolution of linear growth of parts into exponential growth of the whole. Study of the development of individual colonies using a marking technique showed that the development of shape in these colonies proceeded essentially as predicted by the model.
"],"dc:identifier":["https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/209"],"dc:subject":["Cordylophora growth","proline feeding","synchronized peristalsis","exponential colony development","Life Sciences"],"dc:title":["The Biology of a Colonial Hydroid"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T04:11:11Z"}