20 EXPERIMENTS IN THE BREEDING OF CERIONS. 



ered 60 of the planted mollusks. I was told that some visitor had 

 discovered this colony and collected some of the specimens, promismg 

 to replace them, but it is not absolutely known whether this had been 

 done. A single young specimen was also discovered at this time, which 

 showed that they were breeding. The place being deemed unsuitable 

 for the colony, the 62 specimens were transplanted to the iaside of the 

 fort near the center, where conditions appeared to be much more 

 favorable than in the place first selected. As the fort was about to be 

 abandoned, little fear of interference with this colony was expected. 



The Garden Key plantings were examined on April 27, 1914, when it 

 was discovered that the second planting inside of the fort had been 

 completely burned over; 28 dead shells were found, but the rest had 

 disappeared. A visit to the original planting showed 6 living specimens 

 of the original planting, but no young. The place was less overgrown 

 this year than the last. Apparently the cleaning up to which I sub- 

 jected it then had decreased the morning-glory growth and this gave 

 the Cerions a better chance. We left the 6 specimens in a tuft of grass 

 in this place. 



In 1915 no specimens were found in this planting, and in 1916 only a 

 single individual. In neither of these years was there a single trace of 

 Cerions seen on the inside of the fort. 



In 1917 and 1918 this planting was not visited, but on January 16, 

 1919, a careful search was made both within and without the fort, but 

 not a trace of Cerions was discovered, so it is to be feared that this 

 colony has disappeared. 



The Colonies on Loggerhead Key, Tortugas. 



On this key 10 plantings of Cerion viaregis have been made. They 

 bear the letters E, F, G, H, I, K, M, P, Q, and R, and were established 

 in the order listed. We shall discuss them now in this sequence. 



The Loggerhead Key Colony E. 



On June 8, 1912, in a sandy plain covered by a mixed stand of 

 Uniola paniculata and Sporoholus virginicus, 500 specimens of Cerion 

 viaregis were planted near the south end of the island. The place was 

 marked by a stake. 



In May 1913 a large number of young were observed, 55 of which 

 were gathered in 20 minutes in a space of 3 square yards. The young 

 were all about the base of tussocks of grass, some on and some under 

 the surface of the ground. 



In April 1914 we gathered 300 young specimens (some of which were 

 figured in the 1915 report, upper figure of plate 5) and 3 full-grown and 

 3 nearly full-grown individuals (see top row of plate 3 of 1915 report) 

 The young were planted in a small meadow to the northeast of the one 

 m which the present colony is planted. They were marked with a tag 



