[Annals N. Y. Acad. Sci., Vol. XXIV, pp. 1-17, PU. I-V. 1 May, 1914] 



THE USE OF CRINOID AEMS IN STUDIES OF PHYLOGENY ^ 



By Elvira Wood hbrari 



NEW VOR 



{Presented by title before the Academy, 2 March, 19U) BOTANICA 



CONTENTS 



Page 



Introduction 1 



Description of CactocrinuH and six species of the genus 3 



Comparison of the preceding six species 9 



The Gactocrinus niultihrachiatus series 12 



Comparison of the preceding three species 14 



Relation of Cactocrinus to Teleincrinus 15 



Conclusion 17 



Introduction 



In studying the phylogeny of Paleozoic crinoids, the worker is greatly 

 hampered by the difficulty of obtaining information about the early stages 

 in ontogeny. By the time the young crinoid is sufficiently calcified to be 

 preserved in the fossil state, the calyx has nearly, if not quite, all the 

 plates which are to be present in the adult. This fact is illustrated by 

 a calyx of Batocrinus svhrpqnal'is only 4 millimeters in height which pos- 

 sesses all the plates of the adult, with the full number of arms and a 

 well-developed tegmen and anal tube. The present paper is concerned 

 with results which were obtained from a study of adult, or of late neanic 

 stages of camerate crinoids. 



In order to determine the exact amount and character of the varia- 

 tion occurring in the number and arrangement of calyx plates, about one 

 hundred specimens of Batocrinus and Cactocrinus were examined and 

 the position of each plate carefully recorded. From this investigation, it 

 was found that there is very little variation in the plates concerned in the 

 sujiport of the anus. In the specimens of Cactocrinus examined, the only 

 variation in the radial series was found to be due to the presence of an 

 extra arm or one arm less than the normal number for the ray, necessi- 

 tating a greater or smaller number of plates in the calyx. In each case, 

 the plates present followed the normal order for a similar ray or half ray 



' MiiniiKcript rpceivtvl liv tlu» Krtitor. 4 I'obniarv. 1014. 



(1) 



