96 Memorias de la Sociedad Científica 



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



XXVI, p. 149. 1889). 

 Xiphotrí/gon acutidens, Sting Ray £r. Green m;. Shales of Wyo. 



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



Yarrpw's rpt. on Batrach. and Reptil. 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., Coló., N. 



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



VI. p. 639. 1875). 

 Tellowstone Park, The present condition o£ (Am. Nat. XIX. 



p. 1037. 1885). 

 „ „ (Am. Nat. XXIV. p. 255, 1890). 

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



1894). 



Zacualtipan, Hidalgo, México, 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 ("WalHng and Gray's New topograph. atlas p. 



25. Phila. 1873). 

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

 atlas, p. 19. Phila. 1872). 



