SMITHSONIAN EXPLORATIONS, 1 93 1 79 



liiuiuinia, Cerion chrysalis, and Cerion tridentata. Two, Cerion sculp- 

 tum and Cerion species?, seem not to have survived. 



On the morning of September 22 we set out for Key West in the 

 launch Darwin, stopping at Boca Grande Key to determine the state 

 of our Cerion viaregis colony there. This place seems to have been 

 persistently burned over, even the Government beacon about which we 

 scattered our mollusks failing to furnish protection, as it too has been 

 burned down. 



We next visited Man and Boy Keys, and found that on both of 

 these islands the places where our colonies had been planted were 

 burned over. And, as on Boca Grande, not even a single dead shell 

 was to be found. 



On September 2$ we set out for Miami on the Darwin, and made 

 our first stop on New Found Harbor Key. Here we found the hybrid 

 colony Cerion viaregis X Cerion incanuin flourishing. Mr. Munson, 

 the owner of the island, has well kept his promise to protect these 

 mollusks. I took 200 specimens, 100 for cytologizing and 100 for the 

 National Museum collection at Washington. This did not make a 

 serious inroad in the colony. 



Our next stop was on Bahia Honda, where I received several sur- 

 prises. The first was the finding of a thriving colony of Cerion in- 

 canum in the elevated sandy stretch of the southeast portion of the 

 island. In all our previous visits to this key we were unable to find 

 any living specimens of Cerion incanuin. Dead shells, it is true, were 

 buried in the sand in many places, but so were those of Oxystyla 

 undata. I took several hundred of these shells for the collection at 

 Washington. 



The second surprise was a hybrid between Cerion incanuin and 

 Cerion casablancac. These hybrids occur about the junction of the 

 incanum colony and the colony of Cerion casablancac on the south 

 side of the ditch that divides the Cerion casablancac colony. Judging 

 from the great diversity of form among these hybrids, I believe them 

 to represent, at least in part, second generation material. Next to the 

 New Found Harbor Key colony I consider this the greatest return 

 in the hybridization work. Figures 76 and JJ show a hundred of 

 these mollusks ; the specimens are now in the collection of the United 

 States National Museum. 



Still a third surprise was a change in size — even apparent in the 

 field — in the members of the Cerion casablancac colony on the north 

 side of the ditch. Comparing the average measurements, as well as 



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