EXPERIMENTS IN THE BREEDING OP CERIONS. 



47 



Table No. 30. — Measurements of the first generation of Florida-groum Cerion crassUdbris 



from Loggerhead Key Colony L. 



The snails were doing well in May 1916. 



In July 1917 no adult specimens of the first generation were located. 



In January 1919 we obtained 36 adult and 4 almost adult individuals 

 of the first generation, and many tips were in evidence at the base of 

 tufts of grass. The 36 adult specimens were measured and their meas- 

 urements are given in table 30, while the photographs of all the 40 are 

 shown on plate 51. These 40 specimens form the basis of Colony S. 



The Logoeehead Key Colont S. 



This consists of 40 specimens of the first generation of Florida-grown 

 Cerion crassilabris. They were planted in the northwest comer of the 

 large meadow in which Cerion uva (Linnseus) is located. The planting 

 is fringed for a great part by bay cedars and the ground contains a good 

 growth of Cyprus brunneus, Sporobolus virginicus, and a scattered 

 growth of cacti. The planting was marked by a stake bearing a tag 

 with the legend: " Cerion, 1919, S." 



The measurements of the first generation of Florida-grown Cerion 

 crassilabris fall completely within the range of variations noted for the 

 check series excepting in the case of the least diameter, where the 

 Florida-grown shells show several specimens with the diameter a frac- 

 tion of a millimeter narrower than in the check series. 



A comparison of the figures (plate 51) with the check series will reveal 

 that no appreciable change in outline or sculpture has taken place. 

 We may therefore state that, as in the case of Cerion maregis and Cerion 

 casablancce, the changed environment to which we have subjected these 

 specimens has not affected the progeny in any recognizable manner. 



