among 15 genera, or 3.13 to 1. The 15 species described by Dr. 

 Dekay in the Natural History of the State are arranged in 7 ge- 

 nera, a proportion of 2 . 14 to 1 ; or, adding with the sixteenth 

 species of Mr, Gebhard, an additional genus, we have 2 to 1 . It 

 will thus be seen, that instead of a multiplication of genera in our 

 work, their proportional number has actually been diminished. 



The 17 species of New- York Ophidia, as now given, belong to 

 14 of the genera of the Smithsonian Catalogue, or a proportion of 

 1 .21 to 1 ; thus embracing two-fifths of the genera described, al- 

 though the number of species is only one-seventh of those enume- 

 rated as North- American. It is a matter of much interest to find so 

 large a proportion of American genera included within the limits 

 of the State. The generic features will thus become of use in the 

 speedy discrimination of species, as but three of the genera have 

 more than one species to each. 



To facilitate the appreciation of the generic character of the 

 synopsis, as well as to aid in the determination of species, I have 

 added to the present article two plates containing a view from 

 above and on the side of each one of the seventeen species. All 

 these outlines are entirely original, and in nearly all cases taken 

 from New- York specimens. No. 0, or Scotojihis alleghaniensis, I 

 have lettered, so as to correspond with the following explanation 

 of terms. All are the size of life, but the numbers 14, 15, 16, 17 j 

 which are twice natural size. 



