viii VERTEBRATE ZOOLOGY 



often helpful in drawing complex figures, although not necessary ; 

 but in case of their use great care should be taken that they 

 be neatly put on, as the careless application of colors invariably 

 injures the drawing. 



Anatomical terms. No particular system of anatomical no- 

 menclature has been employed in this book, such terms being 

 used as make the descriptions exact and easy to understand. 

 Anterior and posterior indicate the direction toward the front and 

 hind ends of the body respectively; dorsal the direction toward 

 the upper side, and ventral that toward the under side. Lateral 

 indicates the direction away from the- middle, longitudinal plane 

 of the body, and medial the direction toward that plane. Prox- 

 imal and distal are usually applied to portions of an extremity 

 or projection, and indicate the direction toward and away from 

 its base or attached end respectively. A dorsoventral plane passes 

 between the upper and under surfaces of the body, the sagittal 

 plane being the median, longitudinal, dorsoventral plane. 



Materials for dissection. If desired, the animals used for dis- 

 section in this book may usually be obtained, preserved and in- 

 jected, of the following dealers: 



H. Edward Hubert, 3615 Melpomene Street, New Orleans, 

 Louisiana. 



Southern Biological Supply Co., New Orleans, Louisiana. 



Marine Biological Laboratory, Supply Department, Woods Hole, 

 Massachusetts. 



General Biological Supply House, n 77-1 179 East 55th Street, 

 Chicago, Illinois. 



The Anglers Company, 913 West Randolph Street, Chicago, 

 Illinois. 



New York Biological Supply Co., 271 West 125th Street, 

 New York. 



Puget Sound Biological Station, University of Washington, 

 Seattle, Washington. 



Living material can also be obtained from several of the above- 

 named dealers. Living mud puppies are sold by Alexander Nielsen, 

 Venice, Ohio, and by Paul A. Webb, Meadville, Pennsylvania. 



