Polke Eek a Ok. 
Tue publication of the fourth volume of Norrn American Herrerorocy affords 
me another opportunity to thank those gentlemen who have aided me in the 
prosecution of this work, 
To Dr. 8. Barker of South Carolina, I am indebted for many living specimens 
of the Serpents of the lower section of the state, and especially for a magnificent 
specimen of the Pituophis melanoleucus, or Pine Snake. 
Colonel James Frreuson has also procured me several fine specimens of the 
Water-snakes inhabiting Cooper river. 
To Dr. Worpeman I am indebted for many Serpents found among the moun- 
tainous parts of our state, in the neighbourhood of Greenville. 
Dr. Epmunp Ravenet has done much for me in Ophidiology; he has not only 
furnished me with a great number of Serpents, but has made some excellent 
remarks on their habits. 
To our distinguished Icthyologist, D. Humpuriss Storer, M. D., of Boston, I 
owe many thanks for his aid in this volume, and especially for a living 
Tropidonotus niger, or Water Adder, of Massachusetts. 
