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NO. 2177. FOSSIL FISHES IN NATIONAL MUSEUM— EASTMAN. 269 



Genus EDESTUS Leidy. 



Through fortunate discoveries in this country and abroad, our 

 knowledge of the pecuhar structures known as the Edestidae has 

 been hxrgely augmented during recent years, and the number of de- 

 scribed species increased to more than a score. A review of the ex- 

 isting literature was pubhshed by the present writer in 1903,^ and, a 

 decade later, a further review was contributed by A. Karpinsky,^ 

 former Director of the Russian Geological Survey. In the same 

 year appeared an important article b}^ O. P. Hay,^ in which a speci- 

 men named by him Edestus mirus was declared to afford conclusive 

 proof as to the dental nature of the much-del)ated segmented struc- 

 tures. This specimen is noteworthy also for having associated with 

 it in the same block of matrix two Orodus-like teeth, thus suggesting 

 that the segments of Edestus and related genera {Toxoprion, Lisso- 

 prion, Helicoprion) were in reality the fused symphysial teeth of 

 Palaeozoic Cestraciont sharks. More recent contributions to our 

 knowledge of this class of remains are two papers by Karpinsky,* one 

 on the general nature of Helicoprion, the other describing a new spe- 

 cies and a preliminary account of Edestus by Woodward.^ 



EDESTUS HEINRICHI Newberry and Worthen. 



., Plate 6, fig. 1. 



Edestus heinrichi Newberry and Worthen, Pal. Illinois, vol. 4, 1870, p. 350. 

 pi. 1. fig. 1. 



One of the largest and best preserved examples of this species has 

 recently been added to the United States National Museum collec- 

 tion, and catalogued mider the number 8032. It was collected a 

 number of years ago by Mr. William Metcalf from the Coal Measures 

 of Appanoose County, Iowa, and by him presented to the National 

 Museum in 1914. Its total length is about 33 cm, and the niunber 

 of segments indicated by separate teeth and sheaths is ten. Besides 

 these, an eleventh and youngest formed segment, not yet con- 

 sohdated with the fused mass at the time of the creature's death, 

 when it became lost, is indicated by a smooth area on either face 

 of the posterior haH of the common base, where the newly formed 



1 Mark Anniversary Volume, pp. 279-289. New York, 1903. 



2 Karpinsky, A. On Helicoprion and other Edestidae: Verb. Kais. Min. Ges. St. Petersb., vol. 49, 1912, 

 pp. 69-94. 



3 Hay, O. P. On an important specimen of Edestus, etc. Proc. U. S. Nat. Mus., vol. 42, 1912, pp. 31-38, 

 pis. 1, 2. See also the following by the same author: On the nature of Edestus and related genera, with de- 

 scriptions of one new genus and three new species. Proc. U. S. Nat. Mus., vol. 37, 1909, pp. 43-01, pis. 12-15. 

 The specimens of Edestus described in these papers by Doctor Hay are now preserved in the collection of 

 the United States National Museum. They include the tjipes of Edestus crenulatus, E. serratus, E. mirus, 

 and Lissoprionferrieri Hay. 



< Karpinsky, A. Notice sur la nature de I'organe helieoidal du Helicoprion. Bull. Soc. Ouralienne 

 Sci. Nat. d' Ekat^rinebourg, vol. 35, 1915, pp. 117-145. (Text in Russian and French)— A new species 

 of Helicoprion (//. clerci). Bull. Acad. Imp. Sci. St. Petersb., vol. 35, 1916, pp. 701-708. (Text in Rus- 

 sian.) 



6 Woodward, A. S. A new species of Edestus from Yorkshire. Nature, vol. 98, 1916, i)p. 102-103. 



