202 TUE CLASSIFICATION OF THE OPHIDIA. 



The species of this subfamily are all American and mostly Neotropical. The 

 following genera are found in the Nearctic fauna : Carphophiops, Diadophis, Farancia, 

 Rhadinsea (Dromicus flavilatus Cope, from the Southeast Atlantic region, belongs to 

 this genus : PI. XXVII, Fig. 6), Heterodon. Of these all are characteristically 

 Nearctic, except Rhadinsea, which is Neotropical. I have given a synopsis of the 

 genera of Dromicinse in the American Naturalist for October, 1894, p. 840. 



LEPTOGN ATHDSr M . 



The three genera of this family are distinguished as follows : 



Gular region with two longitudinal pairs of plates Petalognathus D. & B. 



Gular region with numerous paired plates LeptognatJms D. & B. 



Gular region with a median plale Mesopeltis Cope. 



The hemipenis in the subfamily Leptognathinse is not bifurcate, but the sul- 

 cus is deeply so. It is calyculate from the bifurcation of the sulcus to the extremity 

 and the calyces are fringed. Below them the organ is furnished with hooked spines 

 half way to the base. Below these the surface is smooth. In Mesopeltis sanniolus 

 the calyces have longer papillae than in the other species which I have examined. 



COLUBBIN^. 



This subfamily includes representatives of the Calamarinse, Coronellinse, Lyco- 

 dontinse, Colubrinse and Dryaclinse of authors, and includes burrowing, ground and 

 arboreal types. The group is especially characteristic of Palearctica and Nearctica, 

 but numerous forms occur also in the Oriental, Ethiopian and Neotropical realms. 

 There is a general similarity in penial structure, the diversities being of minor impor- 

 tance, and some of them not yet fully understood. I have been able to abolish the 

 division Coronellinse, which never had any real standing, and also to show that Hal- 

 lowell was right when he referred the Lycodon rufozonatus of authors to the neighbor- 

 hood of Coronella. The genera of burrowing habits and generally small size which 

 were variously referred to the Calamarinse and Coronellinse, generally have the ruching 

 of the hemipenis reduced and replaced by spines. This is conspicuous in Stylosoma 

 and especially in Conopsis, where there is but one row of calyces, and in Adelphicus 

 and Trimetopon, where the cups are replaced by unossitied papillae. In the species of 

 Ophibolus the calyces are much reduced in number and replaced by spines. Some 

 genera have the borders of the calyces conspicuously papillose, while in others they 

 are smooth, but intermediate conditions connect them. In some forms there are smooth 

 patches on the apex of the organ, but the value of this character is uncertain. In 

 Cynophis I have found a remarkable apical awn, but as I have had the opportunity of 



