iv PREFACE. 



A few general practical directions are given to enable the student to adopt those expedients in 

 tlie examination of specimens wliich experience has shown to be the best. These instructions are 

 necessarily brief, but a detailed account is less necessary since the methods to be pursued are given 

 clearly and at length in Huxley and Martin's Elementary Biology, to which the student is referred. 

 The following features of the Atlas may be specially mentioned : — 

 The names of the various parts are placed on the drawing. 

 Tlie description faces tlie Plate. 

 Colour is used to distinguish the different organs, and as a rule, corresponding parts have 



the same colour througliout in order to render comparison easy. 

 The size of a microscopic object is generally given, or shown by means of squares, to 



prevent misconception. 

 The comparative Histology of Frog and Man shows that a close correspondence exists 

 between the structure of the Frog and that of higher animals, and thus justifies its 

 detailed study as a representative form. 

 Tlie complete life-history is usually given. 

 Separate drawings are freely used for the different systems of tlie Plant or Animal body, 



and thus all the evils and confusion arising from overcrowding are prevented. 

 Equivalent terms allow of its being used with any standard text-book. 

 No apology is needed for issuing a work of this kind. While there are large and well-executed 

 wall-diagrams which the student may admire at a distance, there is no set of drawings at a convenient 

 price and in a handy form which he can use as a map to show him the various regions of the Plant 

 or Animal, and guide him in his attempts to explore them. It is hoped that the cheap and con- 

 venient form of the Atlas may favour its introduction even into higher-class schools. There the 

 study of Biology might be made a powerful instrument, both of information and training, and a 

 valuable preliminary to the study of Physiology. 



"We are much indebted to Mr. S. P. Eastick for valuable aid received wliile the work was in 

 progress. No pains have been spared to ensure accuracy, yet doubtless some mistakes have escaped 

 notice. 



Edinburgh, January 1880. 



