520 British Association • — I 



there can be no doubt the latter is that we stand most in 

 need of. I question whether we shall not be rendering more 

 service to zoology by paying closer attention to the species 

 we are already acquainted with, than by further augmenting 

 the immense collection of uninvestigated forms which now 

 exist in our cabinets. We have, perhaps, sufficient materials 

 on our hands, though not for discovering the whole natural 

 system, at least for solving many important problems in 

 zoology, were we only better instructed in the nature of these 

 materials. It has been shown, in the course of this Report, 

 that there are large groups, even whole classes, of which the 

 true situation and affinities are either not determined at all, 

 or involved in much uncertainty, from the imperfect know- 

 ledge we have of their structure and economy ; and, in the 

 details of the system, there is not one class which does not 

 present many genera, and a vast many more species, in this 

 predicament. Here, then, is where the researches of na- 

 turalists should be directed. Until we shall have more 

 closely analysed the characters of these groups, and learnt 

 both the method of variation and relative importance of all 

 the organs ; until we shall come to understand their whole 

 structure, as compared with those structures we are already 

 acquainted with ; we can neither determine the affinities of 

 these groups, nor of any others allied to them which we may 

 hereafter discover. 



" Researches of the above nature are, perhaps, best em- 

 bodied in monographs. The value of such works has been 

 every day more and more appreciated since the science has 

 become so extensive, and since its legitimate object has been 

 better understood, especially when they refer to every point 

 in the history of the group treated of, and when due care is 

 taken, first, to ascertain what others have written on the same 

 subject. Many excellent monographs fulfilling these con- 

 ditions already exist Nevertheless, it would 



be extremely desirable to have them multiplied. By the 

 help of such works, we may arrive step by step towards a 

 more complete generalisation of the large number of facts 

 embraced by zoology, at the same time we greatly facilitate 

 the researches of other naturalists. But all enquiries into 

 the structure and economy of animals presupposes an exact 

 discrimination of species. Without this, the most detailed 

 observations are rendered of little use, and it is the want of 

 it which detracts from the value of much that has been 

 recorded by those who have not sufficiently attended to this 

 matter. Hence it should be one object of a monograph to 

 investigate species with a view to their exact differences, and 

 to elaborate the synonymes of those which have been noticed 

 by other authors. This is especially necessary in some 



