CLARK! CRINOID FAMILY ANTEDONIDAE 127 



These seeds have the Inventory number 38,696. Other importa- 

 tions are numbered 1928, 1929, and 42,365. 



ZOOLOGY. — A revision of the crinoid family Antedonidae, with 

 the diagnoses of nine new genera. 1 Austin H. Clark, Na- 

 tional Museum. 



The family Antedonidae is the most universally distributed of 

 all the families of recent crinoids; its species occur everywhere, 

 ranging from the tropical littoral in both hemispheres uninter- 

 ruptedly down to the greatest depths at which crinoids have been 

 found, and include all of the strictly antarctic and all of the 

 arctic comatulids. 



Owing to the difficulty involved in dealing with the species of 

 this family, which arises chiefly from the altogether extraordinary 

 brittleness and fragility of the great majority, and the resultant 

 lack of some essential feature or other in very many of the 

 published descriptions, no really satisfactory disposition of the 

 included types has as yet been proposed ; but it is believed that 

 the following arrangement more nearly represents the true inter- 

 relationships of the component species than any of its prede- 

 cessors. 



The species referable to the family Antedonidae fall naturally 

 into forty genera, which in turn are distributed among seven well 

 characterized groups, ranking as subfamilies. These subfamilies 

 with their included genera are the following : 



Antedoninae: Antedon, Compsometra, Mastigometra, Euantedon, Toxo- 



metra, Dorometra (nov.), Eumetra, Iridometra, Hybometra, Andro- 



metra (nov.), and Argyrometra (nov.). 

 Thysanometrinae : Thysanometra and Coccometra. 

 Perometrinae : Perometra, Nanometra, Erythrometra, and Hypalo- 



metra. 

 Heliometrinae : Heliometra, Promachocrinus, Anthometra, Solano- 



metra, Florometra, and Cyclornetra. 

 Zexometrinae : Balanometra, Psathyrometra, Leptometra, Adelometra, 



Zenometra, Sarametra (nov.), and Eumorphometra. 

 Isometrinae : Isometra. 



1 Published with the permission of the Secretary of the Smithsonian Institu- 

 tion. 



