70 SECTIONAL ADDRESSES 



be immaterial in palaeontological perspective. Both James and Elizabeth 

 were of royal ' blood,' and were indeed fairly closely akin. There were 

 many strands common to the tangled ancestry of both ; and, since they 

 belonged to successive generations, Elizabeth could, without disrespect 

 or inaccuracy, be described as in loco parentis to James. Perhaps this 

 idea can be expressed more clearly by prolonging Dr. Bather's analogy. 

 A glance at Cromwell's portrait or behaviour would suffice to show the 

 improbability of his having been the son of Charles I ; and even a palae- 

 ontologist would see in him the introduction of a new lineage. With the 

 coming of Charles II a manifest restoration of the earlier lineage is evident ; 

 and the question as to whether he was the son, grandson or nephew of 

 Charles I is of minor importance. 



Among fossils, a lineage must be considered as a succession of members 

 of a freely interbreeding stock ; no more precise definition is possible or 

 necessary. Even then it has but a theoretical interest ; in reality the only 

 lineages that can be detected are those of morphogenetic succession. 



The palaeontological evidence of evolution is complicated by the 

 incidence of environmental change. So subtle and complete is the sym- 

 pathy between structure and environment that there is a point of view 

 that claims environment, and its corollary the ' struggle for existence,' 

 as a determining factor in, if not a prime cause of, evolution. If, however, 

 we accept the view that environment is an educator, such glorification of 

 its influence appears ridiculous. Education can transform an ignorant 

 child into a learned man, or a normal flea into a performing one ; but it 

 cannot change a gorilla into a chimpanzee nor a whippet into a race- 

 horse. Common sense shows that there must be limits beyond which the 

 call of environment is powerless to evoke response. 



There is a vast body of evidence to show that evolution is, in some 

 measure at least, independent of the incidence of environment. The 

 most satisfactory evidence of this nature is to be found in the fauna of the 

 Chalk. There, in the stillness of the floor of an open sea, conditions 

 remained constant (save for slight temporary irregularities in the depth 

 of the water) for a very long period of time. Many groups of animals 

 persisted through considerable parts of the Chalk stage, and it is reasonable 

 to assume that their representatives in the successive layers of the Chalk 

 are in as direct lines of descent as can ever exist. When we discount 

 slight, often transient, differences of shape that can be correlated with 

 bathymetrical changes, we find clear proof of continuous and directional 

 evolution in many characters. The case of the genus Micraster is classical ; 

 but those of Echinocorys, Conulus, Bourgueticrinus and Inoceramus are 

 equally convincing. In a later paragraph I propose to use Micraster as an 

 illustration of many important phenomena of evolution. 



The two striking aspects of the nature of morphogeny as shown by 

 ' inch-by-inch ' collecting of fossils from the Chalk are, first, the intrinsic 

 character of the successive changes and, second, their directional quality. 

 The course of evolution, seen in a long succession free from appreciable 

 external influence, proves to be straight, or at least direct. Whether 



