NOTICE OF A NEW COELACANTH FISH FROM THE IOWA 



KINDERHOOK 



CHARLES R. EASTMAN 

 Harvard University 



The family of Coelacanth ("hollow spined") ganoids, first pro- 

 posed by Agassiz in 1844, and subsequently emended by Huxley 

 in two important memoirs of the Geological Survey of the United 

 Kingdom (Decades X and XII) , is at present understood as comprising 

 not more than six satisfactorily known genera, among which Coela- 

 canthus itself, Macropoma, and Undina are of paramount importance. 

 The first-named of these, which is typical of the family and likewise 

 of the group Actinistia, enjoys the truly remarkable geological range 

 from the Upper Devonian to the close of the Paleozoic, or, if the 

 evidence of certain doubtful indications be accepted, possibly even 

 higher; the remaining genera continue throughout the Mesozoic, 

 and exhibit such constancy of structural characters as to render 

 the family one of the most compact and well defined in the animal 

 kingdom. 



Attention has frequently been called to the extraordinary conserva- 

 tism and persistency maintained by the group throughout an unusually 

 long life-period. Its singular history impressed both of the distin- 

 guished naturalists to whom we owe our principal knowledge of the 

 family, Huxley's views upon the matter being thus stated by him: 



Bearing in mind the range of the Coelacanths from the Carboniferous [since 

 ascertained to extend from the Devonian] to the Chalk formations inclusive, the 

 uniformity of organization of the group appears something v^fonderful. I have 

 no evidence as to the structure of the base and side-walls of the skull in Coelacan- 

 thus, but the data collected together in the present Decade shows that, in every 

 other particular save the ornamentation of the fin-rays and scales, the organization 

 of the Coelacanths has remained stationary from their first recorded appearance 

 to their exit. They are remarkable examples of what I have called elsewhere 

 "persistent types," and hke the Labyrinthodonts, assist in bridging over the gap 

 between the Paleozoic and the Mesozoic faunae.^ 



I Mem. Geol. Stirv. United Kingdom, Decade XII (1866); reprinted in the supple- 

 mentary volume of the Scientific Memoirs of T. H. Huxley (1903), p. 65. 



357 



