ON THE BATRACHIA AND REPTILIA OF COSTA RICA. 139 



genus belong to Rhadincea, as the E. melanocephala, D. B., etc. In the descrip- 

 tion of this last species three are mingled, as I have ascertained both from a 

 reading of the same and from an examination of the originals in Mus. Paris. One 

 of these is our R. obtusa, the other is the true R. melanocephala, and the third is 

 a species which I described under the name of Lj/gophis nicagus, Cope. Dumeril 

 and Bibron give both the Island of Guadaloupe and Brazil as habitats of their 

 species. I suspect, however, that the specimen of R. obtusa was accidentally 

 introduced into the jar containing the other two, and that it is confined to South 

 America, where it is not uncommon. It is figured by Jan in his "Iconographie" 

 as the second specimen of R. melanocephala. His first specimen of the same as 

 figured is our Lygophis nicagus, a serpent with a diacranterian dentition. The 

 true R. melanocephala is probably confined to Guadaloupe and the neighboring 

 islands. 



It is probable that the Dromicus tceniatus, Pet., D. godmanii, and D loreatus 

 of Giinther, belong to this genus, as does the D. ignitus, Cope. The posterior 

 tooth is a little longer than the anterior in most of the species, and when one or 

 two teeth in advance of it are broken off or shed, the result may resemble the dia- 

 cranterian type of dentition characteristic of Dromicus. Dr. Giinther expressly 

 states that the dentition of his D. loreatus is not of that type. The species of 

 Rhadincea may then be distinguished as follows, with the premise that the charac- 

 ters of those above named are only known to me from the descriptions of the 

 authors who made them known : — 



I. Scales in twenty-one rows. 



Loreal longer than high; three principal bands, with other less prominent ones 

 between them. R. godmanii* 



II. Scales in nineteen rows. 



Loreal longer than high ; nine longitudinal bands. R. serperastra, Cope. 



III. Scales in seventeen rows. 



a. One preocular. 



Loreal higher than long ; sides with dark line above ; a black-edged pale band 



from eye to side ; head pale, lips spotted. R. vermiculaticeps.f 



Loreal high as long ; three broad brown bands ; the light ground color extending 



to the eye ; lips unspotted. R. fulvivittis.% 



* Dromicus godmannii, Giinther. 



f Tseniophis vermiculaliceps, Cope. 

 % Rhadincea fulvivittis, Cope, sp. nov. 



Head small, not very distinct from body. Frontal a little longer than the suture from it to 

 the nasal, and a little shorter than common suture of occipitals, two-thirds as wide as long. 



