82 SMITHSONIAN INSTITUTION 



the greatest and least altitude and diameter of a check series measured 

 in 1920 with the present results, we ohtain the following tahle : 



No. of 

 whorls 



. f Check series 10.92 



Average ' 



\ Rahia Honda series. . . . 10.05 



,-, f Check series 11.1 



Greatest > . TT 



L Bahia Honda series .... 1 1 .4 



T f Check series 10.0 



\ Rahia Honda series. ... 8.6 



This shows plainly that there has been a decided tendency toward 

 dwarfing in all measurements in this colony; the single increase of 

 0.3 of a whorl in one of the hundred specimens seems negligible. It 

 would be interesting to know the factors that are responsible for this. 



We next visited Cerion Key, wrongly listed as Duck Key in 1912 

 when we planted 500 Cerion viaregis here. As on several previous 

 visits, not a Cerion was to be found, the rank grass having completely 

 swamped them. 



Anchoring near Tea Table Key for the night I visited that island 

 at dusk and was very pleasantly surprised to find the colony of Cerion 

 casablancac flourishing to such an extent that I was easily able to 

 pick up 100 specimens from the vegetation bordering the north shore 

 of the island. These are now in the United States National Museum. 



A comparison of the average measurements, as well as the great- 

 est and least altitude and diameter of the check series with similar 

 measurements of the specimens from Tea Table Key, yields the fol- 

 lowing table : 



No. of 

 whorls 



. r Check series 10.92 



Average > „, 



{_ lea table Key series.. 10.^37 



r . f Check series n.i 



Greatest J 



\_ lea Table Key series.. 11.5 



, f Check series 10.0 



\_ Tea Table Key series . . 9.5 



This shows that the Tea Table colony has continued to breed true 

 to type. 



On August 24 we visited Indian Key where a careful search failed 

 to show Cerions. This colony, too, is extinct. 



Later in the day Sands Key and the Ragged Keys were subjected 

 to an equally careful search, but all of these failed to reveal Cerions. 

 The colonies near Miami must therefore be considered wiped out — one 

 of the results of the Florida boom, which changed these keys from 

 primitive tangles into estates and building lots. 



