296 THE EVOLUTION OF THE LI PAROCERATID.E. [vol. lxxiv, 



capricorns developing into bituberculate sphasrocones, which may perhaps 

 unduly hearten the protagonists of orthogenesis, it shows the difficulties that 

 confront the field-geologist until a study like the Author's places facts in a 

 clear light. In its biological development it illustrates the various phases of 

 palingenesis which in ' Yorkshire Type Ammonites ' I have called saltative, 

 cunctative, precedentive. In the last, the hastening in development of one 

 feature faster than another, we seem to have the clue to the origin of species — 

 it makes for diversity of genera ; while tachygenesis, or the earlier acquirement 

 of characters, gives the differences of species. What was the cause of pre- 

 cedentive palingenesis touches the debatable ground between Weismannism 

 and Neo-Lamarckism. I confess to a predilection for the latter — that the 

 variations of the germ-plasm were not fortuitous, but, in some way, reflect 

 modifications of the somatic cells' induced by their responses to differences 

 of environment. Data for solving this problem are required, and evolutionary 

 studies such as those presented by the Author may be of great assistance. 



Time forbids notice of many other interesting points in regard to the 

 Liparoceratidas, but one especially may call for remark. Again and again 

 the genera reach the position of flourishing sphaarocones, only to die out 

 suddenly. By analogy with other Ammonite stocks there should have been a 

 long period of catagenesis in front of them, passing to serpenticone stages 

 again, with loss of ornament, and even with possibilities of renewed ana- 

 genesis. But nothing of this kind seems to happen — each stock appears to 

 come to a dead end at the height of its career, or thereabouts ; while the 

 latest genus of all is the most flourishing sphaerocone of the family. 



In the Geological Table of his abstract the Author places Beaniceras as a 

 Capricorn, though, later, excluding it from the Liparoceratidee. Beaniceras 

 is a catagenetic Capricorn following a unituberculate cadicone : the others are 

 anagenetic capricorns. The family position of Beaniceras is doubtful. It 

 occurs to me to ask where in the Liparoceratids is the unituberculate stage 

 which in other Ammonite stocks precedes the bitubercidate : do the massive 

 ribs of capricorns really represent it ? When he had nearly completed his 

 investigations the Author showed me some of his interesting results, and, if I 

 remember rightly, he had found in the ontogeny of some Liparoceratids traces 

 of a temporary catagenetic Capricorn condition. Now, it may be suggested 

 that there is a non-sequence in the ontogeny of the capricorns (saltative 

 palingenesis) ; that in the phylogeny there was a unituberculate cadicone 

 stage which is omitted in the Capricorn ontogeny, in the same way as the 

 Capricorn stage is omitted in the ontogeny of the sphasrocones ; and that 

 Beaniceras is the genus which has preserved this unitubercrdar cadicone stage 

 in its ontogeny, and shows it fading into Capricorn. Is the temporary cata- 

 genetic Capricorn condition a relic of this ? 



In conclusion, I congratulate the Author on an excellent piece of work. It- 

 is to be hoped that he will deal with other families in the same way, though 

 in some (owing to mineral condition) suitable material is hard to come by, 

 numerous though the specimens be. 



Dr. A. M. Davies congratulated the Society and the Author 

 on a first paper so valuable and so clearly set forth. He confined 

 his comments to one aspect of the subject : What was the meaning 

 of such developments as that from ribbed Capricorn to tuberculate 

 sphaerocone, repeated time after time in the same stock ? Was 

 it adaptation to a changed environment ? He found it difficult 

 to believe this, and felt that we must here face a problem of 

 e volution more fundamental than even that of Darwinism versus 

 Lamarekism, both of which deal with adaptative evolution. He 

 had been led to a conception of a varying 'margin of elasticity' 

 between organism and environment. When this margin is narrow 

 we have strictly adaptative evolution, as in the striking ease of the 



