44 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



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 elsewhere 

 termed " persistent types ;" and, like the Labyrinthodonts, assist 

 in bridging over the gap between the Palaeozoic and the Mesozoic 

 faunas." 



The earliest known American representative of this family 

 is a typical Coelacanth, described as Coslacanthus welleri,^ from 

 the Lower Kinderhook (base of the Mississippian series) of 

 Iowa. Three other species are known from the Coal Measures 

 of Ohio and Illinois, but none from later horizons until we meet 

 with the very remarkable and in some respects degenerate {e. g., 

 as regards loss of certain of its head bones and most of its tail) 

 Diplurus in the " Newark " rocks of the Atlantic border region. 

 So far as known, this genus comprises but a single large species, 

 D. longicaudatus, which is common to both the Connecticut 

 Valley and New Jersey areas. A vicarious form, to use a Ger- 

 man expression, or perhaps what President Jordan would call 

 a " geminate species " or genus,^ is represented in the Perledo 

 limestone of Lombardy by Heptanema paradoxum Bellotti. 



Genus Diplurus Newberry. 

 Supplementary caudal fin prominent, with much elongated 

 pedicle ; fin-rays robust, closely articulated in the distal half ; pre- 

 axial rays of the first dorsal and caudal fins with spinous tubercles. 

 Scales and head bones irregularly striated, and some of the latter 

 finely granulated. 



Diplurus longicaudatus Newberry. 



1878. Diplurus longicaudatus J. S. Newberry, Ann. N. Y. 



Acad. Sci., i, p. 127. 

 1888. Diplurus longicaudatus J. S. Newberry, Monogr. 



U. S. Geol. Surv., xiv, p. 74, pi. 20. 

 1891. Diplurus longicaudatus A. S. Woodward, Cat. Foss. 



Fishes Brit. Mus., pt. 2, p. 409. 

 1905. Diplurus longicaudatus C. R. Eastman, N. J. Geol. 



Surv. Rept. for 1904, p. loi. 



i/oMj-H. Geol., 1908, xvi, p. 357. 



^Jordan, D. S., The law of geminate species. Am. Nat., 1908, xlii, p. 73. 



