Vol. 5] Jordan. — The Fossil Fishes of California. 



137 



different from Knightia alia (Leidy), also found in the Green 

 Eiver shales. K. alia has the body deeper than in K. eoccena,. 



In Knightia the body is more elongate than in Diplomystus, 

 the ventral outline and the post-nuchal region not especially 

 prominent ; the lower jaw is less prominent and the cleft of the 

 mouth less oblique; the scales are much larger, about thirty-five 

 (over sixty in Diplomystus) , and the anal fin and the correspond- 

 ing part of the vertebral column is much shorter. In Diplo- 

 mystus the anal fin has thirty to forty rays, the caudal region 

 having about twenty-five vertebra?. In Knightia there are about 

 fourteen anal rays, corresponding to about fifteen vertebra?. 

 There are in all about forty-one vertebra? in Diplomystus and 

 thirty-five in Knightia. According to Cope, the anterior neural 

 spines in Knightia are without antero-posterior laminar expan- 

 sion. 



Knightia eoccena is perhaps the most abundant fish in the 

 Eocene shales of Green Eiver, in which locality Diplomystus 

 dentatus and related species of primitive herrings abound. 



The name Histiurus Costa (1850), which is perhaps a syno- 

 nym of Knightia, has been earlier used by Agassiz, as an emenda- 

 tion of Istiurus Cuvier, a genus of reptiles. 



Very recently, Dr. Louis Dollo (Bes. Voyage Belgica, 1904, 

 p. 159) has proposed the new generic name Copeichtliys Dollo, as 

 a substitute for the name Diplomystus of Cope, which Dollo re- 

 gards as preoccupied by the name Diplomystes of Bleeker, a name 

 which Dr. Giinther has altered, unnecessarily I think, to Diplo- 

 mystax. In the judgment of the present writer, Diplomystes and 

 Diplomystus are different words, however similar in spelling and 

 in etymology, and the name Copeichtliys is not admissible. 



Family SALMONIDJE. 



Genus Oncorhynchus Suckley. 



Oncorhynchus [1 tschawytscha (Walbaum)]. 



In ferrugineous shales of Post-pliocene Age, from Fossil Lake, 

 Oregon, are found numerous fragments of the jaws, teeth, and 

 vertebra? of a species of salmon which must have reached a con- 

 siderable size. Nothing in these fragments distinguishes the spe- 



