THE OTTAWA NATURALIST 



Vol. XXVII. October, 1913 No. 7 



DOES THE TYPE OF PROTOPAL^ASTER NARRAWAYI 



PRESENT AN ORAL OR ABORAL ASPECT. 



(Plates VIII-IX, Figure 1). 



By George H. Hudson. 



During my first study of this type, careful search was made 

 for items of evidence for both sides of this question and these 

 items were classified and recorded. The evidence was so long 

 and so overwhelmingly in favor of an oral aspect that it was 

 decided not to burden my paper [A]* with it. In the last 

 paragraph, however, I mentioned three of the most important 

 adverse items, anticipated criticism, and promised a defence of 

 my position. Dr. Raymond uses these items, with others, in 

 favor of an aboral aspect [B]. I propose here to weigh carefully 

 his evidence and present some items which are decidedly against 

 his view. 



Infero-Marginals. 



I. The vertical radial outlines of the interradial shown in 

 [A] plate II, fig. 4, and in our present text figure 1 ; together with 

 the transverse vertical outlines seen in [A] plate III, fig. 5; show 

 a markedly convex surface without the slightest degree of 

 summit flattening and such outlines prove conclusively that no 

 interradial supero-marginal ever developed in contact with the 

 exposed surface of these plates. 



II. On the orad margins of each of these plates there are 

 three concavities the central one the most pronounced. They 

 suggest comparison with the hollows or depressions in the plates 

 of Goniasteridae and Linckiidae into which the jaws of the 

 pedicellariae rest when open. Dr. W. K. Fisher writes me that 

 he believes " The impressions are intended to receive the epineural 

 plates," and that they are, therefore, oral surface features. 



"Papers to which reference is made are indicated by capital letters in 

 brackets. A list of these is placed at end of this article. 



