Vol. XXI, pp. 125-136 April 11, 1908 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



NEW GENERA OF UNSTALKED CRINOIDS. 



BY AUSTIN HOBART CLARK, 

 United States Bureau of Fisheries.* 



Some time ago I published a revision of the genus " Antedon " 

 as understood bj" Dr. P. H. Carpenter and most modern 

 workers upon the Crinoidea, in which I divided the group into 

 eighteen genera in an attempt to better bring out the relation- 

 ship of the various specific types. The material at hand at the 

 time was not very extensive, and I was forced to leave certain 

 genera, most especially Antedon (as restricted), in a somewhat 

 unsatisfactory condition ; although I realized that I was " lump- 

 ing" certain well-defined generic types under a single generic 

 name, I did not feel justified in making any further subdivis- 

 ions. Further study and more abundant material have shed 

 much light upon many obscure points, and I am now able to 

 point out certain additional, apparently well-marked and homo- 

 geneous, specific groups. 



My previous paper contains one or two errors, which I take 

 this opportunity of correcting; the pinnules of Calometra are 

 said to be cylindrical, whereas in reality they are sharply trian- 

 gular; this error arose from having studied only wet material, 

 whereas a true idea of the characters of the Comatulida can only 

 be ascertained from dried specimens; I followed Carpenter in 

 placing Antedon diihcni of Bohlsche near Antedon bifida, in my 

 restricted genus Antedon ; it is, however, merely the young of 

 Tropiometra carinata ; Antedon tenuicirra of Carpenter should 

 have been placed in Thysanometra ; it is possibly the young of T. 

 U nelloides, but further material is necessary before they can be 

 united with certainty; the species compressa and orion, placed 



* Published by permission of the Commissioner of Fish and Fisheries. 



17— Proc. Biol. Soc. Wash., Vol. XXI, 1908. U'.tf) 



