INNOCUOUS SERPENTS. ISO 



except in the head and the plates which cover it being less, 

 and in the abdomen being a little angular. Beneath, yel- 

 low, the upper parts of a smoke-grey, sometimes approach- 

 ing to a greenish, sometimes to a bluish hue. S. 140 + 50. 

 R. S. 19. 



I have arranged, as an appendix to the genus Xenodon, 

 an Ophidian of uncertain origin, but which probably comes 

 from Brazil : it is our 



8. Xenodon bicinctus. It approaches the Coronella, 

 and has a pretty robust form. The eye is bordered by a 

 circle of 6 plates, and the rostral is very depressed. The 

 body is surrounded by broad bands or double rings of 

 brown, disposed on a yellowish ground, and forming below 

 square spots. S. 192 + 89. 



HETERODON. 



The snakes of this genus are Coronellas, or rather Xeno- 

 dons, with the head prolonged into a conical muzzle, gene- 

 rally terminated by a hard salient plate, truncated at the 

 extremity. They have only been observed in the New 

 World, where they inhabit sandy places. The other plates 

 of the head are less than ordinarily developed. The pre- 

 dominant colour is red, relieved by spots or rays of a dark 

 colour. These animals do not attain a large size, and the}" 

 are among the rarest of Ophidians. 



1. Heterodon Platyrhinus is the best known, and is 

 distinguishable by its massive and vigorous form, and 

 especially by its turned-up rostral plate, projecting in the 

 form of a crescent ; it has several frontal scales, and the 

 labial plates are very high. Scales lanceolate, carinated, 

 and disposed in 21 rows. S. 124 + 38. Body covered 

 with wide, dark spots, on a reddish-gTcy ground. Coun- 

 try, North America. Brazil produces a climatal variety 

 of the same species. 



2. Heterodon Khinostoma, a native of Brazil, re- 

 sembles the last in the form of its rostral plate ; but this 

 part is smaller in this species ; the plates on the head af- 

 fect a more regulaj' figure ; its scales are smooth, and dis- 



