COPE ON CRETACEOUS AND TEETIARY FISHES, 69 



Depth of body just behind dorsal fin 0.006 



Depth of body in front of dorsal (No. 2) 0. 010 



Five vertebr£e measure (No. 2) _ 0. 017 



Length of ventral fin (No. 2) 0.016 



Discovered by JDr. F. V. Hayden in the Niobrara Cretaceous of 

 Dakota. 



This fish is particularly welcome, as displaying generic identity with 

 a species of the Westphalian Chalk, and with a third, from the Slates of 

 Mount liebanon. It thus indicates a closer relation between these 

 faunse than could be predicated on the discovery of the family to 

 which it belongs. The horizon of Mount Lebanon has been regarded as 

 Eocene, but Heckel and Yon der Marck place it in the Upper Cretaceous. 

 To the conclusion of these palaeontologists, the discovery of this and 

 other species described in this paper lends support. 



ICHTHYOTRiNGA TENUiROSTRis, gen. et sp. nov. 



Character genericus. — Head attenuated and produced into a beak; 

 jaws with weak teeth, of equal lengths. Dorsal tin small, composed of 

 soft rays. Body covered with small, round scales. Yertebrse sub- 

 elongate. 



The specimens representing this genus are so far imperfect that the 

 caudal and anal fins remain unknown. But they show clearly that it 

 differs from the genera which appear to be related, namely, Dercetis 

 and Bhinellus, in the absence of dermal scuta and in the short dorsal 

 fin. But one species has come under my observation. 



Character s^^ecificus.— The- dorsal fin is about half as far behind the 

 cranium as the length of the latter. It is supported by well developed 

 interneural spines; but these elemepts do not exist in front of it. 

 Muzzle very slender, the mouth apparently opening to behind the orbit. 

 The scales closely imbricate, in about twenty longitudinal series, above 

 the vertebral line of the side. Dorsal radii, II. (rudimental), 12. The 

 superior supplementary ribs are numerous. 



Measurements. 



M. 



Length to opercular border 0. 043 



Length to base of first dorsal ray 0. 061 



Length of base of dorsal fin 0.006 



Elevation of dorsal fin 0. 010 



Depth to vertebral column between dorsal fin and head 0. 005 



Five vertebrae 0. 006 



From Cretaceous No. 3 of Dakota {Dr. F. V. Hayden). 



Spaniodon simus, sp. nov. 



Another genus of the Lebanon is represented in the collections from 

 Dakota by a rather abundant species. The elongate anterior teeth of 

 the dentary bone and the edentulous maxillary are exhibited by the 



