ABT, 20 FLORIDA TREE SNAILS — SIMPSON" 9 



direction of the wind during these storms. It is probable that the 

 rock in the westeni end of this former island is of a solider type 

 than that of its eastern part, hence the water was not driven through 

 to any considerable extent but it entered everywhere by seepage and 

 has eroded and dissolved it into a most complicated archipelago. I 

 feel certain that a Liguus^ the forerunner of the forms we have 

 found on these Lower Keys, reached the big island, became estab- 

 lished, and spread over the entire region and that it broke up into 

 several varieties which pretty well occupied the whole area before 

 the dismemberment took place. 



A thin, glassy, inflated form of crenatus was cast ashore on the 

 elevated hammock near Fort Lauderdale, no doubt an early migrant 

 from Cuba to our shores. Later the sea threw up a great sandy bar 

 or bank a few^ miles to the east of this forest, and the intervening 

 space has been filled with a mangrove swamp. The Liguus has been 

 carried down and established on this bank where I found it at the 

 New River mouth and for a couple of miles to the northward. This 

 colony of seftentHonalis^ as Pilsbry has aptly called it, is the 

 farthest north of any in the United States. The form has spread 

 south of New Kiver, it has crossed Little River, and in a hammock 

 just below the mouth of that stream I found nearly pure individuals. 

 Near Arch Creek it has hybridized with one of the forms of fascia^ 

 tus, the shells having exactly the shape, markings, and texture of 

 septentrionalis but a pink axial region. I have shells from the 

 town of Jamaica in Cuba that are very close to this. 



It is probable that at least four forms of Liguus that drifted from 

 Cuba became established at the great Miami hammock. According 

 to the Report of the State Geological Survey some of this land is 

 elevated to a height of 30 feet above sea level, and it is most likely 

 the highest on the southeast coast. It was probably above the sea 

 and was dry land before any other part of this general region and 

 has had a longer time in which it could be colonized by snails. These 

 forms I have called miatniensis, Uvingstoni, tnosieH^ and ebumeus^ 

 the first two belonging to fasciatus^ the latter two to crenatus, and 

 none of them inhabits the Upper Keys. L. mimnien^is is doubtless a 

 hybrid between a form near cnstaneozonaPus and probably a typical 

 fasciatus, the earlier whorls having a broad, more or less broken 

 brown band and the last whorl a pattern of spiral lines, the two com- 

 ing together abruptly, I have shells from Cuba which show similar 

 characters. This form ranges from Ojus to a considerable distance 

 south of Miami. The form livingstoni is a small fasciutivs usually 

 lacking the color pattern on the upper spire, but I have a shell from 

 Luis Lazo, in Pinar del Rio, that is exceedingly close to it in which 

 the color pattern has almost vanished. It is found from Fort 

 Lauderdale south to Long Pine Key. I have large shells of inosieri 



9755&— 29— 2 



