36 PEOCBBDINQS OF THE 



not later tlian the Devonian period, but we still lack a nmltitiule 

 oF links for which we must wait i)atiently until mere iiceident 

 reveals them. AV^e vaguely see that the earliest Dipnoi were more 

 closely related to the earliest Crossopterygii than are the later 

 Dipnoi to the later Crossopterygii. They were therefore nearer 

 a common ancestor. To find this common ancestor, to recover 

 more links, and to explain the problematical Arthrodira, we need 

 fossils of still earlier date than those we already possess, 



Lt.-Col. J. T. TuLL Walsh then moved :— "That the President 

 be thanked for his excellent y\ddress, and that he be requested to 

 allow it to be ])rinted and circulated nmongst the Fellows," which 

 resolution, having been seconded by Sir Nicolas YERMOLOFi', was 

 l)ut and carried w itb acclamation. 



The President having acknowledged the Vote of Thanks, pro- 

 ceeded lo address Prof. Edward Bagnall Poultok, K.ll.S., and 

 handing to him the Linnean Gold Medal. He said : — 



Professor Poulton, — 



The Council of the Linnean Society has awarded to you the 

 Linnean Medal as a token of its appreciation of your long and 

 important services to the advancement of Zoological science. 

 You began by traversing a very wide field, from bone-caves and 

 Pleistocene geology to the structure of the tongues of Marsu|)ials, 

 and you accomplished much histological work which culminated 

 in your interesting discovery of true teeth in the embryo Oniitlio- 

 rhifncJiiis. Your inclination, however, was always towards ento- 

 mology, and you have for many years been regarded as the chief 

 exponent of the phenomena of protective resemblance and mimicry 

 in insects. AA'ith persistent industry you have brought together 

 an immense array of facts from all parts of the globe in support 

 of the view that these appearances are adaptive in their nature, 

 and furnish strong evidence of the potency of natural selection. 

 You have stimulated naturalists and collectors everywhere to 

 observe and record such facts, and to send home illustrative 

 specimens which you have added to the Hope Collection at Oxford. 

 During your tenure of tlie Keepership of this collection, indeed, 

 you have entirely changed its character. From being a vast series 

 of specimens interesting mainly to systematists of the old school, 

 you have made it into a great museum illustrating variation, 

 geograpliical distribution, mimicry, and other phenomena im- 

 ])ortaiit for the theory of evolution. With the co-operation o£ 

 ]Mr. Arthur Sidgwick you have devised an accurate and com- 

 prehensive nomenclature to include all cases of protective and 

 aggressive resemblance, tlnjs clearly marking the difference 

 between the mimicry discovered by Bates, and the cases which 

 fall under the head of " syuaposcuiatic association" as explained 

 by ]M idler. You have also done most valuable experimental work 

 oh " variable protective resemblance," especially demonstrating 



