IV. TUBE-DWELLING KOTIFEKS. 



"At the foundation of all organisation there is an original 

 intrinsic kinship." GOETHE. 



" In truth, nature has no such fancies as those man is ever ready 

 to credit her with. She has but one law endless variety ; and her 

 varieties blend into one another by such fine gradations that no 

 natural system of classification can be other than unsatisfactory, 

 doomed to be destroyed and re-cast by each succeeding generation 

 of naturalists." C. T. HUDSON. 



ALL careful observers are familiar with the grada- 

 tions in the scale of life : every class, whether 

 animal or vegetable, presenting such differences 

 in organisation and habit as indicate a gradual 

 progression towards perfection, with occasional re- 

 lapses, or retrogression. 



In Melicerta ringem (described in No. III.) 

 we have the highest this form has reached ; and 

 between that and the lowest, are several grades 

 approaching more or less closely to perfection. 

 There is M. pilula, for example, which is at once 

 observed to be lower in the scale by the striking 



