Receptaculitaceae is considered an algal family within the order Dasycladales. The family is a coherent group that possesses anatomical characters common with the recent Dasycladales. the geographic and stratigraphic distribution of Silurian recetptaculitids is along the reef belt in a narrow zone from Iowa to Newfoundland. The ecological distribution of most Silurian species is within the reef complex; a few species are found in the carbonate inter-reef facies and a few in shaly rocks. -- The Silurian receptaculitids in North America are represented by three thribes, four genera, and twelve species. the tribe Cyclocriniteae is represented by Cyclocrinites dactioloides and C. gregarius; Calathieae is represented by Calathium egerodae n. sp.; Receptaculiteae consists of Receptaculties and Ischadites; Receptaculties is represented by R. sacculus, and Receptaculites sp., and Ischadites by I. koenigii, I. stellatus, I. abbottae, I. hemisphericus, I. burntensis, I. subturbinatus, I. planoconvexus n. sp., I. prismaticus n. sp., and Ischadites ? sp Includes bibliographical references (p. 97-108) Receptaculitaceae is considered an algal family within the order Dasycladales. The family is a coherent group that possesses anatomical characters common with the recent Dasycladales. the geographic and stratigraphic distribution of Silurian recetptaculitids is along the reef belt in a narrow zone from Iowa to Newfoundland. The ecological distribution of most Silurian species is within the reef complex; a few species are found in the carbonate inter-reef facies and a few in shaly rocks. -- The Silurian receptaculitids in North America are represented by three thribes, four genera, and twelve species. the tribe Cyclocriniteae is represented by Cyclocrinites dactioloides and C. gregarius; Calathieae is represented by Calathium egerodae n. sp.; Receptaculiteae consists of Receptaculties and Ischadites; Receptaculties is represented by R. sacculus, and Receptaculites sp., and Ischadites by I. koenigii, I. stellatus, I. abbottae, I. hemisphericus, I. burntensis, I. subturbinatus, I. planoconvexus n. sp., I. prismaticus n. sp., and Ischadites ? sp Fieldiana series has been published as Geological Series by Field Columbian Museum (1895-1909) and Field Museum of Natural History (1909-1943), and as Fieldiana: Geology by Chicago Natural History Museum (1945-1966) and Field Museum of Natural History (1966-)