OF MASSACHUSETTS. 135 



C. Stages of Development. 

 In order to give a brief consecutive narrative to the life history 

 of the scallop it was found necessary to confine the detailed descrip- 

 tions of the period following the time of " set " to the reference 

 portion of the report. For this purpose the life of the young scallop 

 during the dissoconch and the plicated stages has been arbitrarily 

 divided into eight periods. The chief characteristics of each of these 

 periods are described in tabulated form and refer to the drawings 

 of the early stages. In making the divisions the shell has been taken 

 as the standard, and each stage is differentiated by some change in 

 formation. 



