21 G REPORT OF NATIONAL MUSKUM, 1890. 



Work which has been carried on during the year and has not yet 

 been printed may be summarized as follows : The curator has devoted 

 a large proportion of his leisure to the examination and illustration of 

 the tertiary fauna of Florida, especially that above the Eocene. The 

 first half of the resulting monograph is now passing through the 

 press. 



The second part is fairly well advanced, but will require the writer's 

 attention for some time to come. 



In connection with this investigation the writer has studied, and 

 offers an explanation of, the dynamic process by which the spiral par- 

 allel ridges of the interior of gastropod shells are produced and become 

 amenable to the influence of natural selection. As one of the first 

 demonstrations of dynamical evolutionary processes among mollusks, 

 this paper, it is believed, will be of interest. 



J)r. Stearns has been at work on the West American collections of 

 the Albatross and on sundry interesting southern forms of land-shells, 

 and has prepared for the ethnological department of the Museum a 

 series of shells to illustrate his paper on " Primitive Money " (pub- 

 lished in the Report, U. S. National Museum for 1886-'87), and also a 

 series to illustrate the Indian game of " Ha " and the game of " Props," 

 as described in the paper on that subject referred to in the Bibliography 

 (section iv) of this Eeport. 



Mr. Simpson has in view a revision of the Floridan Unionidce. 



STATE OF THE COLLECTION. 



In previous reports I have explained why it is impossible to give the 

 exact number of species, specimens, duplicates, etc., contained in the 

 collections under my charge. In my last report it was estimated that 

 the collection contained about 408,000 specimens of all sorts, since 

 which about 3,500 specimens have been received, which would make a 

 total of about 471,500 specimens in the collection, of which perhaps one- 

 quarter are preserved in alcohol. 



The total number of entries in the Museum register or catalogue for 

 188S-'89 was 6,323 ; for the present year it was 6,569. The registra- 

 tion, with certain gaps, as exhibited in the following table, terminates 

 with No. 116,920. The total number of registrations to date, omitting 

 duplicate entries and vacant numbers assigned to Professor Verrill, but 

 not yet reported as used by him, is 94,903, representing about 281,700 

 specimens. The number of workers requires the simultaneous use of 

 several volumes of the register, which explains why the following table 

 is necessary to show the registrations for the entire year. 



