DERMATEMYDIDA:. 279 



Genus ANOSTEIRA Leidy. 



Plastron articulating with the carapace by sutures. Plastral bones 9, the entoplastron 

 lanciform. Hinder plastral lobe small. Nuchal bone without costiform processes. Ten pairs 

 of peripherals; 8 pairs of costals; 7 neurals. The eighth pair of costals meeting on the mid- 

 line. Epidermal scutes developt at least on the carapace. The vertebrals greatly modified. 



Type: Anostetra ornata Leidy. 



Dr. Leidy did not definitely refer this genus to any family, but regarded it, with Baena, 

 Chisternon, and Baptemys, as apparently intermediate to the Pleurodira and the Chelydridae 

 (Contrib. Ext. Fauna, etc., p. 341). Cope (Amer. Naturalist, xvi, 1882, p. 990; Vert. Tert. 

 Form. West, 1884, p. 112) arranged the genus under the Chelydrida; but in the same family 

 in close relation with Anosteira he included also Claudius. He arranged Dermatemys among 

 the Emydidtc. Baur (Ann. Mag. Nat. Hist., ser. in, 1889, pp. 58, 276; Proc. Acad. Nat. Sci. 

 Phila. 1891, p. 420) favored placing it with either Staurotypus or Kinosternon, according as 

 the entoplastron might or might not be found to be present. Mr. Lydekker (Cat. Foss. Rept., 

 in, 1889, p. 143) places the genus in the subfamily Anosteirinae under the Chelydridas. Hay 

 in 1902 (Bibliog. and Cat. Foss. Vert. N. A., p. 446) raised this group to family rank, but this 

 had already been suggested by Baur. 



The nearly complete shell described below, presenting as it does the entoplastron, enables 

 us to refer the genus definitely to the Dermatemydidae. The plastron resembles closely that 

 of Staurotypus salvinii. The presence of the costiform processes in the living members of the 

 family are not regarded as being of essential importance. 



There can be hardly any doubt that Pseudotrionyx Dollo, of the Middle Eocene of Bel- 

 gium, is a genus closely related to Anosteira. 



Anosteira ornata Leidy. 

 Plate 43, figs. I, i; teit-figs. 351-354. 



Anosteira ornata, LEIDY, Proc. Acad. Nat. Sci. Phila. 1871, p. 102; Ann. Report U. S. Geol. Surv. 

 Montana, etc., 1871 (1872), p. 370; Contrib. Ext. Fauna West. Terrs., 1873, pp. 174, 341, plate xvi, 

 figs. 1-6. HAY, Bibliog. and Cat. Foss. Vert. N. A. 1902, p. 447; Bull. Amer. Mus. Nat. Hist., 

 xxn, 1906, p. 157, figs. 2, 3. 



Anostira ornata, COPE, Ann. Report U. S. Geol. Surv. Wyoming, etc., 1872 (1873), p. 621; Amer. Nat- 

 uralist, xvi, 1882, p. 989, fig. 7; Vert. Tert. Form. West, 1884, p. 128. DOLLO, Bull. Mus. Roy. 

 Belgique, iv, 1886, p. 93, pi. ii, figs. 7, 8. 



This beautiful and interesting species was based originally on 4 individuals, some of 

 which had been discovered at Church Buttes and others at Grizzly Buttes, Wyoming. Where 

 these types now are the writer does not know. It is possible that some of them are included 

 under No. 4062, of the U. S. National Museum. The specimen figured by Leidy was obtained 

 somewhere in the neighborhood of Fort Bridger. It is now in the collection of the Phila- 

 delphia Academy. All of his specimens appear to have come from the lower portion of level 

 B of the Bridger Eocene. The American Museum expedition of 1903 found fragmentary 

 specimens of the species at Grizzly Buttes and on Cottonwood Creek. The expedition of 

 1905 secured at Henry's Fork a nearly complete shell, which is here described and figured 

 (plate 43; text-figs. 352, 353). This comes from a higher level than the other known specimens. 



Leidy's reconstruction of this species attributed to it ii pairs of peripherals. Dr. Baur 

 was the first to correct this error. The complete specimen just mentioned confirms Baur's 

 statement. 



The specimen found at Henry's Fork belongs to the third division of level C. It has the 

 number 6132, of the American Museum. The specimen is slightly crusht. The neurals 

 (fig. 352) are all missing, as well as the left front part of the carapace. In form the carapace 

 is not so much excavated in front as is represented in Leidy's figure. Other specimens of the 

 species show as little excavation. 



The total length of the carapace (plate 43, fig. I ; text-fig. 352) along the median line is 

 125 mm. The width is 105 mm. The nuchal is slightly damaged, but its length has been close 

 to 20 mm. and the width the same. The free border is subacute; the thickness at the midline 



