1916] The Ottawa Naturalist. 41 



It is so seldom found preserved, that in thirty years' collecting, 

 during which time I collected at one locality more than 6,000 

 specimens, I found only two specimens having this cone-shaped 

 body preserved." In his "Revision of the Blastoidea," (1903, 

 p. 14), Hambach also calls attention to a structure "on the 

 posterior side above the anal opening, on very well preserved 

 specimens, a small proboscis about one-fourth of an inch in 

 length, constructed of small hexagonal pieces, as shown in Figs. 

 6 and 7. To my knowledge it is the first time that such a body 

 has been observed on a Blastoid. I found this appendix on 

 Pentremites conoideus, and have now four specimens of it show- 

 ing this, so far unknown, organ." When, however, Hambach 

 finds the ambulacral area more or less roofed over with small 

 cover-plates, he believes them to be "fragments of broken-up 

 pinnulae," or "small ovulum-like bodies," .... "due 

 to the oolithic character of the rock in which they are imbedded." 

 In the latter case a true structure, rarely found, is apt to be 

 cleaned away, because of a belief that it does not belong to the 

 specimen. It is well here to emphasize the need of most careful 

 scrutiny before any attempt to modify an exposed surface. 



Of Blastoidocrinus it seems that the nearly perfect Valcour 

 Island specimen is the only one ever found still retaining its 

 large "apical plate," its prominent series of "wing plates," 

 (which form above the cover plates and completely hide the 

 latter from view), and its brachioles; yet B. carchariaedens is one 

 of the common fossils of the Chazy limestone. Additionl ex- 

 amples might be given, but the above are sufficient to show 

 that species may be abundant and the mass of collected material 

 very great indeed, and yet valuable evidence be lacking as to 

 morphology, function and relationship. 



From certain resemblances between Blastoidocrinus and 

 some genera of the Edrioasteroidea, and from an examination 

 of the only mechanism apparently used by the latter for the 

 function of food-capture, I am forced to conclude that certain 

 genera now grouped by Bather in this order possessed brachioles, 

 and that purposive search for these structures in additional 

 material, and it may be very fragmental, will sooner or later 

 reveal them. My belief is based on the following facts. 



The Edrioasteroidea are closely allied to the Cystidea, and 

 by many made an order of that class, as in the last edition of 

 Zettel's Text-book of Paleontology (Eastman). Bather follows 

 Billings in recognizing the marked characteristics of this group, 

 but places it no higher than a class of the subphylum Pelmatoza. 

 making it equal in rank to Cystidea, Blastoidea and Crinoidea, 

 All these classes were feeders on minute or microscopic plant 

 and animal forms of the plankton, or on equally small but per- 



