12 NEW YORK STATE MUSEUM 



It is therefore to be assumed that we have before us only the central 

 axis of the organism, which was surrounded by the polypiferous 

 fleshy parts. This central axis was, judging from its carbonaceous 

 character, of horny or chitinoid substance. The outer granular 

 rind is preserved only in rare instances. This, on account of the 

 preservation of the fossil in a sandy shale, where every trace of 

 calcite of all shells is leached out ; and also the fact that mollusks 

 and brachiopods are preserved only as molds would indicate that 

 the rind probably was originally of a calcareous nature. We have 

 then a central horny axis surrounded by a calcareous, or possibly 

 also chitinous, skeleton which in its turn is enveloped by the polypi- 

 ferous sarcode. This is the structure found in numerous Alcyon- 

 arians, notably the Gorgonidae. This structure, combined with the 

 fact that the habit of Plumalina is more similar to that of the 

 Gorgonidae than to that of any other Coelenterata, permits the 

 reference of Plumalina to the order Alcyonaria as conclusively as 

 fossil material will allow it ; for it is still always to be remembered 

 that we lack the polyps themselves and have not the least indication 

 of their shape ; that hence the soft parts might place the fossils in an 

 entirely different taxonomic position and show Plumalina to have 

 been an extinct, very aberrant branch of another class or order of 

 the Coelenterata. This alternative view would, however, obviously 

 leave Plumalina a greater puzzle than before, and moreover, not 

 serve the purposes of paleontologic taxonomy, which is to indicate 

 the nearest relationship to living organisms as far as it can be 

 elaborated. 



The Museum collection contains large slabs with thick structure- 

 less stems of this species which show that the stem branched 

 repeatedly and irregularly. Some stems show an irregular trans- 

 verse wrinkling of the inner axis as if this body had been able to 

 shrink to some extent (see text fig. 3). The pinnulae were appar- 

 ently not articulated for fragments of them of various lengths are 

 seen attached to the stem, while when articulated they would all 

 have come off at the articulation point. The " pinnules " are mostly 

 squarish in section through pressure and frequently show a groove 

 in the middle on the upper and under sides from partial collapse, 

 indicating that they were not very solid. 



Mr David White informed me some years ago that in his opinion 

 Plumalina plum aria can not be a plant, while on the other 

 hand, Doctor Van Name, the zoologist of the State Museum, after 

 studying the structure here figured, considered it well comparable to 

 that of the Alcyonarians. 



