xviii 



eye for minute distinctions, a methodical habit of mind, scrupulous 

 exactness, and an excellent memory. -He spared no pains to clear up a 

 doubtful point, and never satisfied himself with imperfect knowledge, 

 where there was more to be acquired. Continuing to believe in the 

 permanence of species, and opposing the doctrine of evolution, he 

 nevertheless fully recognised the frequency of a wide range of varia- 

 tion ; and his collection, instead of being restricted to type-forms, con- 

 tained many interesting series of varietal modifications. How im- 

 portant is the careful and systematic study of Shells, in relation to the 

 existing geographical distribution of Molluscan species (both terres- 

 trial and marine), and, through this, to the elucidation of the past 

 history of the globe, would not need to be here pointed out, if it were 

 not that among the present generation of naturalists such study finds 

 comparatively little appreciation. It should never be forgotten that 

 (to go no further back in the history of Geology) it was entirely 

 upon the Conchological comparisons of Desbayes, that Lyell founded 

 his division of Tertiary formations into Eocene, Miocene, and Pliocene 

 — a division which has stood the test of fifty years' thorough scrutiny. 

 And it will not be for the advantage of Science, if Conchology should 

 ever cease to attract competent workers. No better model could be 

 set forth of what Conchological work should be, than that which is 

 presented in Gwyn Jeffreys 's life-long labours, whose results are con- 

 tained in the fifty-five years' series of papers (considerably exceeding 

 100 in number) which he communicated to the Societies of which he 

 was a Fellow, and to the pages of scientific Journals. 



It should not be left unmentioned that Gwyn Jeffreys's excellent 

 business-habits caused his financial services to be sought by the 

 Linnsean and Geological Societies, the treasurership of both of which 

 he held for several years ; and that as treasurer also of the Royal 

 Society Club, his social qualities did much to promote its prosperity. 



W. B. C. 



John Christopher Augustus Voelcker was born on September 

 24th, 1822, at Frankfort-on-the-Maine. He was the fifth son, in a 

 family of seven sons and one daughter, of Frederick Adolphus 

 Voelcker, a merchant of that city, who died when his fifth son was 

 only eleven years old. During his years of boyhood, Augustus suffered 

 from very delicate health, which greatly retarded his early education. 

 This he obtained at a private school in the town. About the age of 

 twenty-two he went to the University of Gottingen, chiefly for the 

 purpose of studying chemistry under, and of working in the labora- 

 tory of, Professor Wohler. 



At Gottingen he took the degree of Doctor of Philosophy, in 184(5, 

 the subject of his inaugural dissertation being the composition of tor- 

 toiseshell. 



