330 



Bluefields, Nicaragua, and from Rio Banana, Bonilla, Colom- 

 baria, and Zent, Costa Rica. 



The genus Sihynophis is interesting in its distribution. S. 

 collaris of southern Asia has been compared with S. annulatus 

 of Mexico and Guatemala and found generically identical. The 

 genus is not found in either the United States or South America. 

 Thus it is not, strictly speaking. Neotropical. There are a 

 number of similar cases -which I hope to treat later in a dis- 

 tributional paper. 



Sihynophis seems to have four American species which may 

 be distinguished as follows: 



A. Not ringed; striped anteriorly, uniform posteriorly; 181 ventrals. 



Sihynophis sumichrasti (Bocourt). 

 Henicognathus sumichrasti Bocourt, 

 1886, Miss. Sci. Mex., p. 628, pi. 41, 

 fig. 5; Tehuantepec, Mexico. 

 A A. Ringed; 135-157 ventrals. 



B. Ringed with black, yellow, black, and red anteriorly; uniform or 

 striped posteriorly. . . .Sihynophis annulatus (Dumoril and Bibron). 



Enicognathus annulatus Dumeril 

 and Bibron 1854, Erp. Gen. vol. 7, 

 p. 335, pi. 80, fig. 1 ; Mexico. (I have 

 seen it from Tabasco and Guate- 

 mala.) The British Museum has it 

 from Vera Paz. 

 BB. Ringed throughout. 



C. Ringed with red, yellow, black, yellow, red; snout black, 



Sihynophis venustissimus (Glinther). 

 Henicognathus venistussimus Glinth- 

 er 1894, Biol. Centr. Amer., p. 144, 

 pi. 51, fig C; Matagalpa, Nicaragua, 

 (Also Bluefields, Nicaragua, and 

 Rio Banana, Bonilla, Colombaria, 

 and Zent, Costa Rica.) 

 CC. Ringed with red, black, yellow, black, red; snout white. 



Sihynophis zeteki Dunn. Ancon, 

 Canal Zone, Panama. 



In addition to the original locahties for specimens of the 

 genus Trimetopon (Cartago and San Jose, Costa Rica), specimens 

 have been seen from La Palma, Turrialba and Reventazon 

 (= La Junta), Costa Rica, and from Ancon and Pedro Miguel 

 in the Canal Zone. These are easily divisible into three species, 

 two of which need naming. 



