252 IOWA GEOLOGICAL SURVEY 



displaced far forwards, and has to accommodate itself to the 

 contours of the suborbital and lower postorbital, it suffers con- 

 siderable reduction in size, whereas in the form under discus- 

 sion it is fully as large as either of the superjacent postorbitals, 

 and is ornamented in similar manner. 



No indications are to be observed in the specimen before us 

 of a sclerotic ring, although one may be inferred to have been 

 present as in other known Coelacanths. Neither is there any ex- 

 ternal indication of the presence of an ossified air-bladder, for 

 which members of this family are remarkable. The caudal, anal 

 and pelvic fins are too imperfectly preserved for description, 

 and the pectoral pair is altogether wanting. The squamation is 

 admirably shown, especially in the posterior part of the trunk, 

 where the fine longitudinal ridges of ganoine and concentric 

 growth-lines are pyritized. The lateral line is rendered con- 

 spicuous by a single large raised tubule of ganoine extending for 

 nearly the entire length of each scale in this row. An enlarged 

 view of the superficial ornament of scales lying a little above 

 the anal fin is given in Plate III, Fig. 7. 



Formation and locality. Basal member of Kinderhook lime- 

 stone, near Burlington, Iowa, beneath a bed carrying an inver- 

 tebrate assemblage of markedly Devonian aspect. Holotype 

 preserved in the Walker Museum of the University of Chicago. 



Genus PdLAEOPHlCHTHYS, novum. 



An aberrant Crossopterygian genus provisionally referred to 

 the Coelacanthidae, and distinguished from all other members of 

 the family by its elongate, anguilliform body, and continuous me- 

 dian fins. Scales very delicate with exceedingly fine antero- 

 posterior striations. Neural and haemal spines long and deli- 

 cate, almost filiform. 



Although the scope of this Report is limited in a strict sense 

 to forms of fish life of Devonian age, yet on account of the great 

 rarity and peculiar organization of the older Coelacanths in 

 this country, it has been deemed advisable to include a notice 

 here of a remarkable specimen from the famous Mazon Creek 

 locality of Illinois, which differs notably from all other genera 

 and species thus far described. We propose to recognize it, 

 therefore, under the following caption: 



