1915.] NATURAL SCIENCES OF PHILADELPHIA. 29 



NOTES ON THE WATER SNAKE NATRIX COMPRESSICAUDA. 

 BY T. BARBOUR AND G. K. NOBLE. 



Natrix compressicauda} and its four hitherto described subspecies are 

 confined wholly to Florida, where they inhabit the brackish lagoons 

 and estuaries of the sea. Since specimens of this water snake are rare 

 in collections, the systematic relationships of the several forms have 

 not been thoroughly determined and any data on this subject should 

 be of interest. Having examined some fifteen adults and a brood 

 of fifteen young from the collection of the Museum of Comparative 

 Zoology, we have found a remarkable variability in individuals 

 from the same locality, while those from different localities have not 

 shown any peculiar characters correlated with their distribution. 

 The young from one brood are dichromatic and show many of the 

 same variations as the adults, and seem to make it certain that 

 there is but a single variable form to be recognized. 



Mr. A. G. Reynolds, of Gulf port, Fla., who has collected a large 

 proportion of the known specimens of Natrix compressicauda, is 

 familiar with this variability of color in fresh specimens. In a letter 

 of September 23, 1914, he writes: 



"I have never found it anywhere except in brackish or salt water. 

 Its local name is the 'salt-water moccasin.' The fishermen occa- 

 sionally find it plentiful among the keys, but they never get me any 

 specimens, although I offer a good price for them. It seems to be 

 more or less plentiful at Key West. Here we get a straw-colored 

 variety, also a variety with one row of spots beneath, and a variety 

 with three rows of spots beneath." 



With the exception of one specimen, the entire series in our col- 

 lection was taken by Mr. A. G. Reynolds. All but one of these 

 have been taken within the last few years and come from different 

 parts of the region of Tampa Bay and Key West. One of the 

 Tampa Bay specimens, kindly loaned for examination by the Academy 

 of Natural Sciences of Philadelphia, comes from Tarpon Springs 

 and was collected by S. N. Rhodes, in 1896. The others from this 

 region were taken at St. Petersburg by Mr. Reynolds. 



1 Kennicott, Proc. Acad. Nat. Sci. Phila., 1860, p. 335. 



