224 Zoological Society : — 



in the latter family, and to see whether it were possible to keep up 

 a West-African Coronelline form of Snakes with the maxillary teeth 

 gradually increasing in strength, for which the name of Meizodon 

 might be retained, I was induced to re-examine all the other African 

 Coronellidce. But I could not convince myself that such a genus 

 would form a naturally defined group. Coronella cucullata, with 

 its posterior maxillary tooth grooved ; Ahlahes rufulus, with all the 

 teeth equal in length ; Coronella olivacea, C. fuliginoides, and pro- 

 bably C. semiornata, with the posterior tooth longest ; and finally, 

 the three species of Meizodon, with the teeth gradually increasing 

 in strength, — are so similar to each other in the proportions of the 

 single parts, in the arrangement of the shields of the head, in their 

 physiognomy, in the structure and number of the scales, in the dark- 

 ness of the colours, that the other character, that of dentition, must 

 give way for generic distinction — the more so as it is very difficult 

 in many specimens, even in some species *, to say which of the dif- 

 ferent categories of dentition is prevalent. 



I add, for completeness' sake, the diagnosis of Meizodon regularis : 



Coronella (Meizodon) regularis. 



Syn. Meizodon regularis, Fischer, Hamb. Abhandl. Gebiet Na- 

 turwiss. 1856, p. 112 ; Gthr. Catal. Col. Snakes, pp. 109, 250. 



Scales smooth, in nineteen rows ; anal bifid ; two posterior oculars. 

 Eight upper labial shields, the fourth and fifth coming into the 



orbit. Entirely blackish-olive ; each scale with a black centre and 

 a pearl-coloured speck at the upper edge ; posterior part of the neck 

 with a broad, darker, lighter-edged collar. 



Hab. West Africa. 



The typical specimen is in the Hamburg Museum ; another in the 

 Collection of the British Museum. 



Coronella (Meizodon) bitorquata, n. sp. 



Scales smooth, in nineteen rows ; anal bifid ; two posterior oculars. 

 Eight upper labial shields, the fourth and fifth coming into the orbit. 

 Brownish-olive above ; a black band across the occipitals, a second 



* In many specimens of Ablabes rufulus the teeth are, strictly speaking, not 

 equal, but increase in strength posteriorly, In Liophis cobella the character of 

 the longer posterior tooth is little marked ; and there are specimens in which all 

 the teeth are of equal size. 



