EXPERIMENTS IN THE BREEDING OF CERIONS. 



39 



east side of the path, 600 feet north of the Ughthouse. This colony- 

 was marked by a stake bearing the legend: "Cerions, 1912, A." 



In May 1913 our animals were doing well and without much diffi- 

 culty we discovered 82 young, one having as many as 7 postnuclear 

 whorls. The cacti seemed to be making altogether too much progress 

 in their invasion of this field, so we thinned them out materially. 



In April 1914 we easily gathered 615 young in various stages of 

 growth, from mere nepionic tips to adults; 20 adult of the first genera- 

 tion were figured in the 1915 report, plate 2, top and bottom rows, as 

 well as a lot of young on plate 4 and bottom figure of plate 5. The 100 

 specimens represented on the lower figure of plate 5 were marked and 

 planted as colony 6, while the 500 tips represented on plate 4 formed 

 the initial planting of Colony B. The 20 adult specimens were fully 

 discussed in the 1915 report. 



Table No. 22. — Measurements of the first generation of Fhrida-grown Cerion casablancce 



from Loggerhead Key Colony A. 



* Altitude estimated; shell not adult. 



In June 1915 we re-examined this colony and found it doing exceed- 

 ingly well. It had spread materially ; adults and young were seen every- 

 where within a radius of 50 feet from the stake marking the spot where 

 the planting was first made. Some of the mollusks had taken to the 

 fringe of bay cedars and had even crossed the path and were in the 

 bushes at the western end of it, but preferred the grass in the shade of 

 the shrubs. In 1914 we had placed 162 of the originally planted mate- 

 rial at the base of the stake. Of these, we found 56 dead in 1915. The 

 removing of the epiphragm and replanting them during the bright part 

 of the day may have affected them adversely, and while we were easily 

 able to find 217 adult and 47 young Florida-grown individuals in this 

 colony, we refrained from measuring them because we feared that they 

 might represent a mixture of first and second Florida-grown genera- 

 tions, so we allowed them simply to remain as they were. 



In 1916, 1917, and 1919 this colony was found in a most flourishing 

 condition. When visited in January 1919 the ground everywhere was 

 covered with adult and young. They had crossed the path and entered 



