96 Memorias de la Sociedad Cientific 



Xenacanthina, Rev. o£ Brogniart and Doderlein on (Am. Nat. 



XXVI, p. 149. 1889). 

 Xiphotrygon acutidens, Sting Ray fr. Green riv. Shales of Wyo. 



(Am. Nat. XIII. p. 333. 1879). 



Yarrow's rpt. on Butrach. and lieptil. 1871-174 (Geog. and geol. 



expl. W. 100 Merid. V. Ch. VI. p. 522. 1875). 

 Yarrow and Cope's rpt. on fishes in Nev., U., Cal., Colo., N. 



M., Ariz. (Geog. and Geol. explor. W. 100 Merid. V. ch. 



VI. p. 639. 1875). 

 Yellowstone Park, The present condition of (Am. Nat. XIX. 



p. 1037. 1885). 

 „ (Am. Nat, XXIV. p. 255. 1890). 

 Youthful Reporter, The (Open Court. Chicago. VIII. p. 4118. 



1894). 



Zacualtipan, Hidalgo, Mexico, Rept. on coal depos. near (Pr. 



A. P. S. XXVI. 122. p. 1. 1885). 

 Zittel's "Handbuch der Paleontologie" etc. Rev. (Am. Nat. 

 p. 1018. 1888). 

 ,, manual of paleontology, Rev. of (Am. Nat. p. 1014. 

 1887). 

 Zoology in the National Parks (Am. Nat. p. 708. 1884). 



,, of Maryland (Walling and Gray's new topograph. 



atlos p. 16. Phila. 1873.) 

 „ ., Ohio (Walling and Gray's Now topograph, atlas p. 



25. Phila. 1873). 

 „ „ Pennsylvania, Sketch (Walling and Gray's topogr. 

 atlas, p. 19. Phila. 1872). 



