G. F. Eaton — Collection of Triassic Fishes at Yale. 259 



Aut. XXYIII. — Notes on the Collection of Triassic Fishes at 

 Yale; by G. F. Eaton. (With Plates V and YI.) 



In 1870 the collection of Triassic fishes made by Messrs. 

 W. C. and J. H. Redfield, and generally known as the "Red- 

 field Collection," was presented to the Yale Museum, with the 

 understanding that it should be arranged and placed on exhibi- 

 tion as soon as opportunity served. The gift was acknowledged 

 in the annual report of the Sheffield Scientific School, 1870-71 ; 

 but for various reasons most of the specimens remained unex- 

 amined in the store-rooms of the museum for nearly thirty 

 years. Meanwhile, good material of the same geological age, 

 received from other sources, has greatly enhanced the value of 

 the Yale collections. 



Semionotus. 



In preparing these Triassic fishes for exhibition, an attempt 

 was made to follow Prof. Newberry's classification, as proposed 

 in his monograph on the Triassic Fishes and Plants.* His 

 arrangement, however, was not found entirely satisfactory. 

 Especially was this the case in regard to the genus /Semionotus 

 ( Ischypterus J , under which some of the specific definitions are 

 uncertain guides in identifying specimens, because of the lack 

 of characters offering any real contrast between the different 

 species named. Fortunately most of Prof. Newberry's types 

 are preserved in the Yale University Museum and in the 

 Columbia University Museum. After a careful study of these 

 and of all other accessible material, the present writer has been 

 enabled to state additional characters to some of the species 

 described in Prof. Newberry's work; while, on the other hand, 

 it still seems advisable to leave many forms in the doubtful 

 list to which they were relegated by Dr. A. Smith Woodward. f 

 Indeed it appears probable that Prof. Newberry's enthusiasm 

 led him to describe more species than are now warranted by 

 the better and larger collections available for study. Well 

 aware of the difficulties he encountered in classifying such 

 imperfect and indistinctly preserved material as the American 

 Triassic fishes, Prof. Newberry himself graciously made easier 

 the task of reducing the number of species by stating that 

 intermediate forms might ultimately make reduction necessary. 

 It is significant that in Dr. Woodward's Catalogue, only two 

 of the American species are deemed worthy of description 

 under the genus Semionotus (synonymous with Ischypterus) , 

 the remainder being merely listed as doubtful and probably 



*Mon. U. S. Geol. Surv., No. xiv, 1888. 

 fCat. Foss. Fish., British Mus. Nat. Hist., pt. iii. 



Am. Jour. Sci.— Fourth Series, Yol. XV, No. 88.— April, 1903. 

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