40 TROPIDONOTUS RIGIDUS. 



scales, notched at their posterior extremities; the inferior row of scales on each 

 side is smooth. The tail is rather long, and compressed or triangular. 



Colour. The whole superior surface of the Tropidonotus rigidus is brown, 

 slightly tinged with red. The abdomen is yellow, slightly shaded with reddish- 

 brown; — each plate being marked near the centre with two oblong dusky spots, 

 which do not extend throughout the whole plate; these spots are so disposed as to 

 form two parallel dark lines on the belly, which terminate at the vent. 



Habits. I am unacquainted with the habits of this reptile, having never seen 

 but one or two alive. 



Dimensions. Length of head, 1 inch; length of bod}', 14 inches; length of tail, 

 6 inches: total length, 21 inches. In the specimen here described, there were 

 133 abdominal plates and 51 sub-caudal bifid plates. 



Geographical Distribution. The Tropidonotus rigidus first appears in the 

 neighbourhood of Philadelphia, where it is exceedingly rare. In Louisiana and 

 Mississippi it is abundant, doubtless, as I have seen a great many specimens from 

 the former state. 



General Remarks. Say first observed this reptile in Pennsylvania, and gave 

 a very good description of it in the Journal of the Academy of Natural Sciences 

 of Philadelphia. 



