No. 2.] EMBRYOLOGY OF THE AMERICAN ALLIGATOR. 203 



lifter with moistened surface being at hand, I make two incis- 

 ions with sharp-pointed scissors on opposite sides of the 

 embryo ; inserting the lifter, it is pressed upward on one side 

 just enough to sever the lateral connections, and then the 

 opposite side is similarly treated. 



This separates a portion of the blastoderm containing the 

 embryo, and measuring about 12 to 15 mm. on the side, 

 from the remainder ; the lifter, kept as close to the embryo as 

 possible, so as to carry the least amount of yolk with it, is now 

 firmly pressed upward against the opposite or distant side of 

 the freed part of the blastoderm and gently but steadily drawn 

 towards one : if all goes well, the embryo comes out in beautiful 

 shape without even a wrinkle. Of course it sometimes fails, and 

 it always requires the greatest care, patience, and steadiness. 

 The embryo is placed on a slide and treated with Kleinenberg's 

 picric for sections, or chromic preferably for surface study. I 

 have found the embryos very difficult to stain, and after a long 

 immersion in cochineal, alum, or borax carmine, I find it neces- 

 sary to put them in alcoholic carmine to insure staining of the 

 innermost parts. 



BIBLIOGRAPHY. 



(1) Agassiz, L. — Contributions to the Natural History of the United States. 

 Vol.11. 1857. Embryology of the Turtle. 



(2) Balfour, F. M. — On the Early Development of the Lacertilia, etc. — 

 Quar. Jour, of Micro. Science. Vol. XIX. 1879. 



(3) Balfour, F. M. — Comparative Embryology. Vol. II. Chap. IX. 



(4) Bartram. — Travels through East and West Florida. 1791 . Page 128. 



(5) Bemmelen, J. F. Van. — Die Halsgegend der Reptilien. — Zool. Anz. 

 X. 1887. 



(6) Clarke, Samuel F. — The Nest and Eggs of the Alligator. — Zool. 

 Anz. No. 290. 1888. 



(7) Goode G. Brown. — The Fisheries and Fishery Industries of the United 

 States. Part II. — " The Useful Aquatic Reptiles," etc. By F. W. True. 

 Page 141. 



(8) Hoffmann, C. K. — Contribution a l'Histoire du DeVeloppement des 

 Reptiles. — Arch. Nterlandaises d. Science exactes et Nat. XVII. 1882. 



(9) Hoffmann, C. K. — Beitrage zur Entwicklungsgeschichte der Reptilien. 

 — Zeit. fur wissen. Zool. XL. 1884. 



(10) Hoffmann, C. K. — Weitere Untersuchungen zur Entwicklungs- 

 geschichte der Reptilien. — Morph.Jahrb. XI. 1SS5. 



