84 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



XI. The Preparation and Exhibition for the Louisiana Pur- 

 chase Exposition. 



Your commission has prepared for the St. Louis Exposition an 

 exhibit to represent the investigations on the hfe history of marine 

 food animals of Rhode Island and methods of their artificial propa- 

 gaton. Inasmuch as some of this work was done in collaboration 

 with the United States Fish Commission, the exhibit is to be in- 

 stalled in the LTnited States Fisheries Building. The following is 

 a brief explanation of the nature of the exhibit. 



A collection of specimens has been made and arranged to illus- 

 trate, as far as possible, the features of economic importance which 

 our investigations have brought out: 



1. A series of about fifty groups of clams illustrates the rate 

 of growth of these specimens during the first three 3^ears under 

 various conditions, location, soil, transplanting, etc. 



2. A series of twenty groups of scallops illustrates the growth 

 of these animals during the first two and a quarter years and shows 

 the origin of the growth ring, by means of which seed scallops may 

 readily be distinguished without reference to size. The great ma- 

 jority of scallops fail to reach the age of two years, and it is gener- 

 ally believed that all die before arriving at that age. A continuous 

 investigation, however, has revealed the fact that some specimens 

 live through the second year and probably breed a second time. A 

 second ring of growth also appears on the shell at the beginning of 

 the third year of life which is similar to that appearing at the begin- 

 ning of the second year. The exhibit contains specimens of scallops 

 two years and four months old showing the two growth rings. 



3. A series of star-fish illustrates the larval swimming form, the 

 manner of setting, the change of the larvae into the adult, and the 

 rapid growth of the star-fish up to the time when each arm is 1^ 

 inches long. The most extraordinary difference' in the rate of 



