1311-12. j ^29 



Professor Carpenter in the course of his address said-^-To-day 

 the general principle of evolution is on almost all hands accepted. 

 The precise value of natural selection in the evolution theory is 

 still, and is likely to remain, a matter of dispute. 'With regard to 

 the general evolutionary idea, it was noteworthy that Darwin was 

 led to it by his observations on the recent and extinct faunas of 

 South America when he travelled there during the memorable 

 voyage of the Beagle. Since Darwin's death many gaps in our 

 knowledge of the geological record have been at least partly filled, 

 and groups of specialised animals once regarded as isolated have 

 been brought into touch with more generalised extinct relations. 

 Within the last few years the historic Devonian quarry of 

 Kiltorcan, in County Kilkenny, has yielded the fossil remains of 

 an undoubtedly Isopod Crustacean — Oxyuropoda of Carpenter 

 and Swain — which proves the existence in Paleozoic times of 

 woodlouse-like organisms. Devonian rocks contain also the oldest 

 known fossil Insects, and the morphological researches of Dr. H. 

 J. Hansen and others have now established a somewhat close 

 relationship between Insects and Crustaceans — possibly a special 

 relationship between Insects and the Woodlouse group. The 

 presence of a pair of minute appendages behind the mandibles 

 in Springtails and Bristletails corresponding to the maxillulae of 

 Crustacea was pointed out by Hansen, and I have lately been able 

 to demonstrate these structures in the primitive armoured larvae 

 of certain Beetles (Dascillidae). They occur also in the Symphyla 

 and in the most primitive Millepedes, and a close numerical 

 correspondence in the segmentation of all the principal classes of 

 the Arthropoda is highly probable. From these thoughts on the 

 general " doctrine of descent " we turn to a few of the explanations 

 of the method of evolution that have been put forward. The 

 discussion as to the relative importance of the Darwinian factor 

 of " natural selection " and the Lamarckian factor of " use- 

 inheritance " still goes on, not always in the most strictly scientific 

 spirit. Natural selection explains readily adaptive characters that 



