INTRODUCTION. XIX. 



Frontispiece. To admit as mucli light, and to obstruct 

 the view of the specimens as little as possible, the upper 

 wooden frames of the table cases are reduced to the narrow- 

 est limits consistent with firmness and security. In the 

 upright compartment the top, bottom, and ends, as well as 

 the sides, are of plate glass, and if a shelf is required it is 

 made of the same material. To give readier access to the 

 specimens, both sides of the upper compartment fall. To 

 exclude the dust, piano-forte hinges are used; each frame 

 closes on double strips of velvet ; zinc gutters underlie every 

 crevice ; and in addition to the locks, bolt-screws are used, 

 which by a half-turn bind the frames closely down in every 

 part. 



As text -books for students of Zoology, the following works 

 may confidently be recommended : A Manual of Zoology, by 

 Henry Alleyne Nicholson, M.D. ; and Introduction to the 

 Study of Biology, by the same Author. Published by 

 W. Blackwood and Sons. 



