PREFACE. ix 



or fanciful coinbiuatioiis, or him who merely wislies to know 

 a species by name. It contains tlie only full and tletailed 

 technical descriptions hitherto given in this country. The 

 habits of the species are treated of with equal extension in 

 every case where I have been enabled to study them advantage- 

 ously. The internal structure has been explained in so far 

 as I have thought it expedient to endeavour to bring it into 

 view, and, in particular, the alimentary organs, as determin- 

 ing and illustrating the habits, have been carefully attended 

 to. If imagination has sometimes been permitted to inter- 

 fere, it has only been in disposing ascertained facts so as to 

 present an agreeable picture, or to render them easily intel- 

 ligible by placing them in relation to each other. 



W. MACGILLIVRAY. 



Amerbeex, Crown Street, 

 ZUt Jubj, 18-32, 



