ANIMAL PEDIGREES 237 



cation of the former possession of a larger quantity. 

 Concerning the later stages our knowledge is 

 incomplete, but so much as has been ascertained 

 gives no support to the suggestion of general 

 degeneration. 



Our knowledge of the conditions leading to 

 degeneration is undoubtedly incomplete, but it 

 must be noticed that the conditions usually asso- 

 ciated with degeneration do not occur. Amphioxus 

 is not parasitic, is not attached when adult, and 

 shows no evidence of having formerly possessed 

 food yolk in quantity sufficient to have led to the 

 omission of important ancestral stages. Its small 

 size, as compared with other vertebrates, is one 

 of the very few points that can be referred to as 

 possibly indicating degeneration, but by no means 

 proving its occurrence. 



A consideration of much less importance, but 

 deserving of mention, is that in its mode of life 

 Amphioxus not merely differs, as already noticed, 

 from those groups of animals which we know to 

 be degenerate, but agrees with some, at any rate, 

 of those which there is reason to regard as primitive 

 or persistent types. Amphioxus, like Balanoglossus, 

 Lingula, Dentalium, and Limulus, is marine, and 

 occurs in shallow water, usually with a sandy 

 bottom, and like the three smaller of these genera 

 it lives habitually buried almost completely in the 

 sand, into which it burrows with great rapidity. 



I do not wish to speak dogmatically. I merely 

 wish to protest against a too ready assumption 

 of degeneration ; and to repeat that, so far as I can 



