the other entitled ‘« Genera,” referring to the distinctions upon which 
some of the more remarkable genera are founded. To what extent they 
may severally go, the Author has not absolutely decided ; probably not 
beyond 50 or 60 altogether; but this will necessarily be determined 
by circumstances. 
In the final Number the general characters of the order will be 
given, with references to the plates which will at that time have been 
published. It is proposed upon the same occasion to explain Mr. Bauer’s 
views of the structure and functions of the different parts of the sexual 
apparatus, and to shew upon what evidence his theory of their mode of 
impregnation is founded. This most interesting subject cannot be pro- 
perly treated of sooner, because it is probable that every plate that the 
Work may contain when complete will be required for the illustration 
of the enquiry. 
London, November, 1830. 
