TO 



ROBEE.T KAYE GREVILLE, Esq., LL.D., 



EDINBTJEGH, 

 AND TO 



GEORGE WALKER ARNOTT, Esq., LL.D., 



PKOFESSOE OP BOTANY, GLASGOW, 



WHOSE lABOUES 



IN BOTANICAL, AND ESPECIALLY BEYOLOGICAL SCIENCE, 



AEE EXTENSIVELY KNOWN AND HIGHLY APfEECIATED, 



Z\)iB 3Littl£ Wiaxk 



IS, WITH EYEEY SENTIMENT OF EESPECT AND ESTEEM, 

 DEDICATED, BY THEIE GEATEFUL FRIEND, 



THE AUTHOE. 



