ART. 20 FLORIDA TREE SIT AILS SIMPSON" 21 



Caipensis and lossmanicus may be recent arrivals through the Bahia 

 Honda Channel. 



Seven subspecies of Liguus inhabit both upper and lower ends of 

 the upper chain of keys but all save suhoreyiatus and lineolatus are 

 totally missing in the center of the chain, and they are replaced by 

 forms of solid-US, which appear to have developed from grafkicus. 

 Long Key, which has good hammock, seems to have no Ligu^s. 

 During the last general subsidence the Upper Keys went down enough 

 that all the LIguus in the center of the chain save suhcrenatus and 

 lineolatus were drowned out, and these subspecies probably survived 

 on a bit of dry land at the northeast and higher end of Lower 

 Matecumbe. All the snails of Long Kej' were drowned and no others 

 have reached it since. During a local but slight elevation of the 

 center of these keys a gravid graphicus landed on the first-named 

 island, where it multiplied and broke into variations, some of which 

 drifted to some of the near-bj'^ islets. 



In Cuba and the Florida Keys the Liguus have for ages occa- 

 sionally come down from the trees when gravid and, obeying an 

 instinct for founding new colonies, have wandered off into the forest, 

 stopping and making a slight excavation where they lay their eggs 

 and fulfill their mission. But in the southeastern part of our State 

 the hammocks are scattered throughout the pineland, which is hostile 

 to the snails. However, they obey this call that has been inherited 

 from thousands of generations that have lived under different en- 

 vironment and strike out into the pine woods in search of hammocks. 

 No doubt most of them miss finding a hammock and perish; others 

 find one and create a colony which continues the race in a different 

 locality. 



Although there have been several oscillations since the great sub- 

 sidence of early or middle Pleistocene, yet they have been but slight 

 and in all were never great enough to drown out the snails or high- 

 land vegetation on the greatest elevations or to make dry land of 

 the bays on the southeast coast of our State. 



Notwithstanding the fact that all that I have narrated has taken 

 place since early Pleistocene, the briefest bit of geological time, yet 

 I feel sure that long ages were required for the development of lower 

 Florida and to people it with Liguus. There was much migration, 

 much hybridizing, the development of new forms, and time was 

 needed for them to adapt themselves to their environment. The 

 whole must have taken many thousands of years. 



The death knell of these beautiful snails in Florida has been 

 sounded, and it will be but a few years until all are gone, save it 

 may be in the great Royal palm hammock which is a State reserva- 

 tion. Most of the small hammocks have been destroyed, and in 

 others still standing the snails are fading away before man. In my 



