EXPERIMENTS IN THE BREEDING OF CERIONS. 19 



On April 29, 1914, it was discovered that the grass had been burned 

 about the beacon and that most of our specimens had been roasted. 

 Quite a number of young, however, were present in the tufts of grass 

 not consumed by fire, and 3 adults and 1 nearly grown of the first 

 Florida-grown generation were found. These are illustrated by the 

 last four figures of the bottom row on plate 3 of the 1915 report. 



On June 25, 1915, we again visited Boca Grande Key and collected 

 119 specimens of the first generation of Florida-grown Cerions; 107 of 

 the adult specimens and 9 of the young, after being marked, measured, 

 and photographed, were replanted on this key about 300 feet south of 

 the beacon, a little nearer the bushes than the shore. A Tournefortia 

 bush standing on the edge of the shore marks the intersecting line 

 opposite which the planting was made. The measurements of these 

 appear in table 4, and for the figures see plates 12, 13, 14. 



On June 4, 1916, when we again visited Boca Grande, the beach had 

 been burned over and our second planting, consisting of the first 

 generation of Florida-grown individuals, seemed completely destroyed. 

 In the original planting, however, a few shells were seen on the grass 

 (Uniola paniculata} about the beacon and many more were observed 

 in a little meadow of Sporobolus virginicus, which is separated from the 

 outer beach by a fringe of low bushes. It is possible that this remnant 

 of the colony may rehabilitate this planting. 



On July 18, 1917, on revisiting Boca Grande, the colony in the little 

 meadow immediately inside of the fringe of bay cedars near the beacon 

 appeared to be doing well, but no shells were found in the location of 

 the second planting. 



On January 6, 1919, we reexamined the planting on Boca Grande 

 and found a few mollusks about the beacon and a goodly number in 

 the little meadow within the fringe of bay cedars, where they had 

 spread for fully 100 feet. No trace of the planting of the first genera- 

 tion of Florida-grown individuals had appeared, and since it is impossi- 

 ble to tell whether the specimens about the beacon belong to the first 

 or second generation, no attempt will be made to utilize them in our 

 discussion. Our experiments for the time being, therefore, have ceased 

 so far as this colony is concerned, and the only further interest that 

 they present will be to see what changes, if any, may occur. 



THE COLONY ON GAKDEN KEY, TORTUGAS. 



On June 8, 1912, a planting of 138 specimens of Cerion viaregis was 

 made back of a small house on the northeast side of the fort on 

 Garden Key. This planting was visited on May 2, 1913. At this time 

 the place, which is a beach of coarse calcareous sand, was occupied by 

 a sparse growth of Sporobolus virginicus and Uniola paniculata and a 

 rank growth of the goatfoot morning-glory, Ipomcea pes-caprae. I 

 cleared a space of 10 by 20 feet by the use of a pocket knife and recov- 



