1888.] NATURAL SCIENCES OF PHILADELPHIA. 405 



Pisa, Rome, Naples, Sorrento : returning through Venice, Florence, 

 Turin, Geneva, Chamouni, Berne, Mayence ; the Rhine, Cologne, 

 Brussels, Antwerp and back to London, Liverpool and home, in the 

 autumn. 



Now, naturally imbued with the love of truth exclusively for the 

 truth's sake; possessed of the true methods of scientific inquiry, and 

 equipped with the results of his life-long home studies of the mol- 

 lusca, as well as of his observations in the European museums and 

 cabinets, Mr. Tryon devised the plan of his greatest work — Manual 

 of Conchology — and promptly began its execution. 



The plan embraced four series of volumes. The first series of 

 ♦eleven or twelve volumes is devoted to the marine univalves ; the 

 second, of six or seven, to the terrestrial mollusca ; the third, of four 

 or five, to the marine bivalves, and the fourth, of four or five vol- 

 umes, to the fluviatile genera. 



The Manual of Conchology, completed according to the author's 

 plan, will consist of from twenty-one to twenty-nine octavo volumes, 

 all fully illustrated. 



The scope of this great work is described in the " advertisement " 

 or preface of the first number, which was finished and ready for pub- 

 lication in the last week of December, 1878. Mr. Tryon says, the 

 Manual " will include, in systematic order, the diagnoses of all the 

 genera and higher divisions of the mollusca, both recent and fossil, 

 and the descriptions and figures of all the recent species ; together 

 with the main features of their anatomy and physiology, their em- 

 bryology and development, their relations to man and other animals, 

 and their geological and geographical distribution." 



The numbers of tlie first series were issued quarterly. Volume 

 IX was completed December 1887. The nine volumes include 3125 

 pages of text, illustrated by 680 plates of 12.055 figures. 



The first number of the second series — terrestrial mollusca — was 

 distributed January 1885, and thereafter quarterly to the close of 

 Vol. Ill, December 1887. The three volumes contain 942 pages of 

 text, illustrated by 187 plates of 6,434 figures. 



Conscious that he probably might not live to complete his enter- 

 prise, but without foreboding, Mr. Tryon interested Mr. H. A. Pils- 

 bry in it. To him he freely imparted his purposes and views in 

 connection Avith it, so that he might continue the publication, should 

 it become necessary. Mr. Pilsbry, who had the unreserved confi- 

 dence of the author, has succeeded him in his ofiice and will edit 



