Vlll 
PREFACE. 
referred to in the text. Most of the discoveries 
alluded to have undergone a careful microscopical 
examination. 
Accurate figures add very much to the value of a 
work of this sort ; we have therefore drawn, with the 
few exceptions mentioned below, the anatomical and 
physiological illustrations either direct from the objects 
themselves, from our microscopical preparations, or 
from photo-micrographs taken by us specially for this 
purpose. These illustrations are figures i, 2, 3, 4, 5, 
6, 7, 8, 9, 10, 15, 16, 17, 18, 19, 22, 28, 30, 31, 34, 
36, 4 h 5 ?y 52, 53j 57, 5^, ^2, 63, 64, 66, 67, 68, 69, 
70, 71, 72. The following illustrations are copied 
from — Witzgall, frontispiece; Hicks, ii; Kraepelin, 
12; Wolff, 13, 14, 21, 23, 39, 40, 43, 51; Marey, 20; 
Macloskie, 24; Claus, 25; Girard, 26, 27, 53; Brandt, 
29; Dujardin, 31, 32; Hyatt, 35; Krancher, 37; 
Schiemenz, 38, 47, 48, 49, 59; Lowne, 44 ; Grena- 
cher, 45, 46; Leuckart, 54; Gravenhorst, 61, 65; 
Vogel, 56; Lucas, 60. We have also introduced a 
few diagrams to illustrate more clearly the functions 
of different parts. Where there is any confusion in 
the nomenclature of the different terms we have 
adopted Kirby’s terms. 
