1879.] natural sciences op philadelphia. 249 



Terminology, etc. 



There is considerable confusion in the literature of Crinoids 

 even among contemporaneous writers as to the terms emploj'ed 

 to designate the different parts of the animal. It is to be regret- 

 ted that there is not some means of establishing uniformity in this 

 respect, as this would no doubt promote better results in investi- 

 gation. We believe it to be especially desirable, and for the in- 

 terest of science, that there should be a better understanding on 

 this subject between Zoologists and Paleontologists, so that the 

 same terms ma} 7 be used, so far as possible, for similar parts in 

 both fossil and living forms. We will not assume to say how this 

 should be brought about, but would be glad to see it undertaken 

 by those of more experience and authority in both fields. 



To avoid misunderstanding of our work we give herewith a list 

 of the principal terms employed, with the definitions as under- 

 stood and used by us. We do not seek so much to introduce new 

 terms as to select the best in" our judgment of those already 

 known to our branch of science, and then to use them consistently. 



Explanation of Terms. 



Boot = extremity of column, where attached. 



Gyrrhi = radicular appendages, springing from the periphery of 

 column joints, or in Comatula from the centro-dorsal plate. 



Column or stem = jointed cylindrical structure below the body. 



Body = the frame of the animal, excluding column and arms. 



Test = the calcareous shell inclosing the internal organs. 



Calyx = the dorsal cup, or the test of the abactinal or dorsal side 

 up to the arms = aboral side. 



Vault, dome, summit = the test above the arms ; the plated cover- 

 ing on the ventral side = oral side = actinal side. 



Ventral sac = vertical extension of the vault in its posterior area, 

 closed at the extremity. 



Anal tube or proboscis = posterior vertical elongation of the vault, 

 with anal opening at its extremity. The term " proboscis" is 

 so generally used that we feel compelled to retain it, although 

 there is a serious objection to its use. The word implies that* 

 it is an oral organ used for feeding, which is, beyond the 

 slightest doubt, directly contrary to the fact. 

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