128 REMINISCENCES OF 



with the ecderon and enderon suggested by Huxley 

 at a somewhat later period. Mine were based upon 

 the two soft tissues, cartilage, and membrane with 

 which the mineral substance became organically 

 united. Huxley's were based upon the two opposite 

 directions in which the two processes of calcification 

 extended themselves; the first outwardly and the 

 second inwardly, each starting from a line to which 

 our author gave the name of " protomorphic." The 

 most interesting of my discoveries were based upon 

 the various modes in which these two forms of bone 

 growth arranged themselves amongst the different 

 types of fishes. Few educated persons, in these days 

 of Darwinian thought, are ignorant of the fact that, 

 alike in the animal and vegetable kingdoms, life pre- 

 sents a succession of forms from the lowest to the 

 highest types. Not that all the links of these chains 

 are living now. Vast numbers of them existed only 

 during the immeasurable ages of the past, of these 

 we only obtain glimpses here and there, through the 

 labours of the geologist and the palaeontologist. 



By turning my attention alike to recent and fossil 

 forms of bone, scale, and tooth, I was able to fill in 

 some links of their chain of organisation, which the 

 living forms alone could not have taught. But 

 even amongst the living animals we find a pro- 

 gression not only in entire races, but in indivi- 

 duals ; and in each of these latter we find similar 

 development in the successive stages of life de- 

 pendent upon advance of age. Dealing with the 



