Of the forms common with other regions there arc Pound : — 



1. In the /Ethiopian region speciee of Rhinoatoma, Philodrytu, 

 Aha inllft, Dryophia, Leptodeira, Dipeadoboa — in fad all the species 

 belonging to these genera show severally, according to the different 

 region, such different characters as may be hereafter considered to 

 be generic characters, if they arc again to be found in other bd 



of the same region ; and I wish therefore to poinl out a much greater 

 difference between both regions than mighl appear by the number 



of forms mentioned as common. For instance, the South American 



species of Rhinoatoma exhibit a posterior grooved tooth ; in Rhino- 

 atoma Ctipreum of Africa I found the same tooth not grooved ; if Rh. 

 occipitaleoi Hallowed from Western Africa, or other species hereafter 

 to he discovered, should prove to have also smooth teeth, I should 

 consider it to he a character sufficient to separate the Neotropical 

 Bpecies from those of the Western Palaeotropical region. Not know- 

 ing the species of PhUodrytu from Madagascar, I refrain from giving 

 my opinion in that respect. 



2. In the Indian region species of Rhabdpaoma, Tomodon, Spilotea, 

 Coryphodon, Dryophis, Eudipsoa, Dipaodomorpkua, — I have already 

 pointed out that South America exhibits in more than one respect 

 similarities with the middle region of the Palaeotropical ones ; and 

 thus, except those forms which are represented in both regions In 

 different genera, we have two genera truly common to them, Rhab- 

 doaoma and Coryphodon. The other genera I reckon of the same 

 account as those mentioned as common with the .Ethiopian region. 



3. In the Palaeotropical region one species of Tachymenia. 



4. In the Nearctic region Bpecies of Heterodon, Herpetodryaa, 

 Coryphodon. The first two genera are limited to the New World, 

 one exhibiting more species in the northern part, the other more in 

 the south. 



The Ophidians decidedly show that the West Indies are referable 

 to the Neotropical region only. Hardly one Bpecies* is common to 

 them and to the Nearctic region, and only the genus Herpetodryaa 

 might he considered such. On the other hand, many Southern con- 

 tinental species are again found in the West Indies; and how many 

 generic forms are common to both, the number of genera marked 

 above with a cross (f) will represent. The genera peculiar to the 

 West Indie-, ami marked with an asterisk (*), do not express a 

 common peculiar character, and some of them are founded on rela- 

 tively Blight characters. 



* HaHoweU mentions heknognathus dekayi -^ found in Jamaica 

 Nat. Sc. Philad. 1S3C. p. 233 . 



