PREFACE 



Parts 3, 4, and 5 of Volume 1, Bulletin 82, include the systematic discussion of 

 the species and higher groups of living comatulids, or unstalked crinoids. Part 3, 

 published on March 21, 1931, included the account of the superfamily Comasterida. 

 Part 4a, published on August 5, 1941, included the account of the superfamily Maria- 

 metrida, with the exception of the family Colobometridae. Part 4b, the present part, 

 is a continuation of Part 4a and contains the account of the family Colobometridae 

 of the superfamily Mariametrida, and of the families Tropiometridae, Calometridae, 

 Ptilometridae, and Asterometridae of the superfamily Tropiometrida. 



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