shells made at Mazatlan in 1848-50, by Frederick Keigen, a 

 Belgian gentlemen, and believing it conducive to the interests 

 of science, he made a most thorough and critical examination 

 of the abundant material it contained. The result of his labors 

 appeared in the " Catalogue of the Eeigen Collection of Mazat- 

 lan Mollusca in the British Museum," which he was induced 

 to make by the late Dr. John E. Grray, then at the head of 

 that institution, to which he presented the collection, consist- 

 ing of eight thousand eight hundred and seventy-three speci- 

 mens, mounted on two thousand five hundred and twenty-nine 

 glass tablets. He entered upon this work with diffidence, as 

 he remarks in the catalogue, " I undertook the work, trusting 

 that its acknowledged deficiencies might in some measure be 

 compensated for, by great patience and care in the faithful use 

 of those means of information which were within my reach. I 

 have endeavored to make it a companion to Professor C. B. 

 Adams' extremely valuable catalogue of the Shells of Panama, 

 which belong to the same great tropical fauna of Western 

 America." 



In the pursuance of his investigations, the variation of spe- 

 cies as suggested by intermediate forms, led him to i^resent 

 his views on the importance of study in this direction, and he 

 was requested by the British Association " to prepare a report 

 on the present state of our knowledge with regard to the Mol- 

 lusca of the West Coast of North America," which was pub- 

 lished in the Transactions of the Association for 1856, and at 

 once took rank as a most able and conscientious work. 



For various reasons — among others his bias for Natural His- 

 tory — he abandoned the ministry, and in 1859, he visited 

 America, " and for some time was engaged in determining 

 and arranging collections of shells presented to the Smithso- 

 nian " and other institutions. 



The following year he married Miss Minna Meyer, of Ham- 

 burg, an estimable lady, who survives him. 



In August, 18G4, a supplementary report on West Ameri- 

 can Mollusca was printed, the object of which was as he says, 

 " to correct the errors which have been observed in the first 

 Report," and to present additional information since derived 

 " from fresh sources." This latter was " marked by the same 

 wide range of thought and depth of study " as the first, and 

 has since been re-published by the Smithsonian Institution. 



