LINNEAN SOCIETY OF LOJfDOK. 39 



like those of Eegaii * on tlie general morphology, and o£ Hide- 

 wood t on the axial skeleton of existing groups, are enhanced in 

 value by the contributions made by palaeontology. We have seen 

 that the earliest known El;isuiol)ranctis almost realise the ancestral 

 vertebrate type as now conceived. Very soon the remnants ot" 

 lateral fin-foiils, which must liave acted merely as two pairs 

 of balancers in these tishes, concentrated into paddles, and these 

 again passed into stout-based fins adapted for swimming. After 

 this advance, the upper jaw-cartilages, which had already been 

 supported by contact with the postorbital region of the skull, 

 gradually assumed a firmer connection with its base in the 

 Bradyodonts which eventually became Chimserojds, while they lost 

 their direct support in nearly all the modern sharks and skates 

 which depend on the hyomandibular and a ligament for jaw- 

 suspensiou. After the differentiation of the jaws, vertebral 

 centra began to appear, and finally there were additional growths 

 and various fusions of cartilages which led to the diversity in the 

 Elasmobranch skeleton observed to-day. Fossils are gradually 

 adding to our knowledge of the successive stages through which 

 this ultimate diversity arose, and we may hope soon to be able 

 to trace most groups of sharks and skates backwards to their 

 generalised common ancestors. 



Mr. Percy Thompso.n^ then moved : — " That the President be 

 thanked for his excellent address, and that he be requested to 

 allow it to be printed and circulated amongst theFellous," which, 

 after being seconded by Mr. J. C. Shenstone, was put and carried 

 by acclamation. 



The President liaving acknowledged the Vote of Thanks, pro- 

 ceeded to address Dr. Dukinfielb Henky Scott, F.R.S., 

 reciting his services to Botany and handing to him the Linnean 

 Gold Medal. He said :— 



Dr. Scott, — 



The Council of the Linnean Society desires to express its 

 appreciation of your numerous and valuable contributions to 

 botanical science by awarding to you the Linnean Medal, the 

 liighest distinction in its power to bestow. Since your first 

 paper on the development of articulated laticiferous vessels, 

 written 40 years ago, you have continued to devote yourself to 

 structural botany with unflagging zeal, and your published 

 memoirs are modnls both for the exposition of new facts and for 

 the concise statement of morphological conclusions. Your early 

 researches soon brought you into association with the late Prof. 

 W. C. Williamson, whose pioneer work on the structure of the 

 petrified plants found in certain coal-seams was attracting wide 



* Prop. Zool. Soc. 1900, pp. 722-758, with figs, 

 t Phil. Traus. vol. 210B (1921), pp. 311-407. 



