Vol. XXII, pp. 173-178 September 14, 1909 



PROCEEDINGS /<fn^ '^ 



OF TUE 



BIOLOGICAL SOCIETY OF WASHINGTON /^ 



NEW GENERA AND. HIGHER GROUPS OF UNSTALKED 



CRINOIDS. 



BY AUSTIN HOBART CLARK. 



The recent increase of our knowledge in regard to the inter- 

 relations of the various genera and species of coniatulids has 

 indicated that there are a number of well-defined groups which 

 it would be advantageous to recognize in nomenclature in order 

 that their relationships may be the more readily understood. 



In my work upon the phylogenetic significance of the syzygy 

 I brought out the reason why the syzygies are always associated 

 with the oblique type of muscular articulation while with the 

 straight type only synarthries ("bifascial articulations") are 

 found. Two important exceptions to tins rule are found in the 

 Comasteridfe in the genera Comaster and Comatula ; in the former 

 all the non-muscular articulations, except the second, occurring 

 in the division series, and the first articulation of tlie free arm, 

 are supposed to be syzygies, while in the latter the primibrachs 

 and secundibrachs, as well as the first two brachials, are always 

 described as syzygially united. Now according to the phylogeny 

 of the syzygy as I understand it the occurrence of syzygies proxi- 

 mal to the third brachial of the free arm is quite anomalous and 

 can not be logically explained. These two genera, therefore, 

 have caused me considerable uneasiness, and it was with some 

 impatience that I awaited material available for dissection in 

 order to confirm or to disprove the anomalous structure of the 

 animals. I have now at hand a large series of Comatida pecti- 

 nata and Comaster novsegidnese from the Philippine Islands. In 

 Comatida. pectinata I find that the supposed syzygies between the 

 primibrachs and first two brachials are in reality synarthries, 

 though the union is very close and certainly appears syzygial in 



27— Pkoc. Kioi,. Soc. W.\sh., Vol. XXII, I'.iO'.i. (173) 



