APPENDIX A. 147 



IVerodia nisrer, B. & G. — Head ellipsoid, anteriorly blunt, flattened 

 above. Vertical jjlate very long, subliexagonal, slightly concave ou the 

 sides. Three postorbitals. Loral and nasals proportionally large. Dorsal 

 scales in 23 rows. Color nearly uniform dark-brown on the back, macu- 

 lated on the flanks and abdomen. 



Stn. Tropidonotus niger, Holbr. N. Amer. Herp. IV, 1842, 37. PI. ix. 

 ^Vater Adder. 



Body more slender, and head larger than in N. sipedon, though 

 provided with 23 rows of scales, all of which are carinated. The 

 scales of the outer row, however, are very large, proportionally more 

 so than in N". sipedon, the nearest relative of this species. The pre- 

 frontals are triangular. The vertical plate is more elongated than in 

 iV. sipedon, whilst the occipitals are smaller. The nasals and loral 

 are also larger, as are the labials, though their number is the same 

 in both species. The prefrontals are triangular. 



Ground-color chestnut-brown, with the scales streaked with black 

 on the dorsal region, whilst the flanks are mottled, so as to appear 

 darker. The head beneath, and the middle of the abdomen on the 

 anterior portion of the body are yellowish. The sides of the abdo- 

 men, and posterior portion of body and tail, are densely maculated 

 with black, almost entirely black beneath the tail. 



From the Cabinet of the Academy of Natural Sciences. 

 Massachusetts. 141+1. 66. 23. 28^ 6 J. Dr. D. H. Storer. 



]¥erodia rliombifer, B. & G. — Vertical plate elongated, narrow, 

 sides nearly parallel. Dorsal scales 27 ; scales all carinated. Postorbitals 

 two on one side, three on the other. Labials 8, 6th highest. A dorsal 

 series and a lateral on each side of quadrate blotches ; the altei'uating 

 blotches of opposite sides connected across the back by dark lines passing 

 into the dorsal series. 



Syn. Tropidonotus rhomlifer, Hallow. Proc. Acad. Nat. Sc. Philad. VI, 

 1852, 177. 



Ground-color light brown, or when the epidermis is removed, 

 bluish ash. The dorsal dark spots are 50 in number from the head 

 to the tip of the tail, the 35th opposite the anus. The lateral bars 

 alternate with the preceding : they extend between the edges of the 



