26 HAV. [Vol. II. 



Xiphactinns aiidax, and which, without doubt, belongs to the 

 Saurocephalidae. A more complete description and figures of 

 this fossil spine were given by Dr. Leidy in his Contribiitiojis 

 to the Extinct Vertebrate Fauna of the Western Territories, 

 p. 290, PI. XVII, Figs. 9, 10. This was published in 1873. 



Professor Cope first recognized the affinities of this spine in 

 a paper in Hayden's Second Antiiiai Report of the Geological 

 and GeograpJiical Siii'vey of the Territories, 1871, p. 418, where 

 he assigned it to the genus Saurocephalus, in which genus he 

 also arranged the species which he later called PortJiens than- 

 mas. He compares the spine with one obtained from S. prog- 

 nathns, a fish which he later relegated to the genus Ichthyo- 

 dectes, itself a close relative of Portheus. From about this 

 period up to 1874 Professor Cope held the opinion that certain 

 fin remains belonged to Portheus, and probably to the pectoral 

 fin, which it is now pretty certain belong to Protosphyraena. 

 Other spine-like fin rays, whose resemblance to Leidy's Xiphac- 

 tinus he admitted, he regarded as also belonging to Portheus, 

 and probably to the ventral fins. He claimed, however, that 

 Xiphactinus was distinct from both Portheus and Ichthyo- 

 dectes ; but he does not specify the points of difference. By 

 the time of the publication of his Cretaceous Vertebrates in 

 1875, he had become convinced that the fin structures which 

 are now assigned to Protosphyraena did not belong to Portheus ; 

 and to them he gave the name Pelecopterus. He had also 

 learned that the ventral spine-like fin rays of his Portheus did 

 not differ greatly from those of the pectoral fin (p. 204). Of 

 Xiphactinus he says : " Dr. Leidy applied the name Xiphacti- 

 nus to a genus indicated by a spine in some degree like those 

 regarded above as ventrals of Saurodontidae. Whether it 

 belongs to any of the genera above enumerated, or, if so, which 

 of them, is a question which can only be settled by future 

 investigation " {op. eit., p. 190). 



Accompanying a considerable collection of specimens of Por- 

 theus collected for me in Western Kansas, in the region of Butte 

 Creek, are many large spines, some nearly complete, others in 

 fragments. Some of these belong to the shoulder girdle which 

 I have figured (Fig. 9), and this, I have no doubt, belongs to 



