144 MEDICAL ZOOLOGY. 



Other Species. C. consors (Kansas). C. tergemznus (Western States). 

 C. edwardsii (New Mexico and Texas). C. kirtlandii (Western States). 



Ancistrodon. Nine plates on top of head. No rattle. One pair of oc- 

 cipitals ; larval between the nasal and anterior orbitals. Labials excluded 

 from orbit by the presence of suborbital plates. Scales carinated ; rows 23 

 in number. Subcaudal scutellae divided posteriorly. Sometimes a small 

 plate between the vertical and post frontal. 



A. contortrix (Copperhead), Baird and Girard. 



Loral plate present. Labials not entering 1 into orbit. Dorsal rows of 

 scales 23. Color light chestnut, with inverted darker blotches on the sides. 

 Labials yellowish white. 



Habitat. United States. Terrestrial. 



A. piscivorus (Water moccasin), Baird and Girard. 



No loral. Inferior wall of orbit constituted by third labial ; 25 dorsal 

 rows. Dark chestnut brown, with indistinct vertical dark bars. Line from 

 superciliary along edge of head through middle of second supralabial row. 

 A second line from the lowest point of the orbit parallel to the first. 



Habitat. United States. Aquatic. 



(2) Viperidae. No pit on side of face. Head plated. Upper jaw toothless, 

 with large fangs in front ; lower toothed. Ventral shields broad, band-like. 

 Head large behind ; subcaudal scutes single. 



Vipera (Viper). Vertebral, occipital, and superciliary plates sometimes 

 distinct ; front of head with small shields ; nose blunt. 



V. berus. 



V. aspis. 



Habitat. Western and Southern Europe. (Gray.) 



Cerastes. Subcaudal plates two-rowed ; nostrils lunate, in the hinder part 

 of a small nasal plate ; superciliary shields very small, scale-like. Scales 

 keeled, broad, ovate, rounded at end, placed in oblique, cross series; keel 

 not reaching the tip. (Gray.) C. cornutus. N.Africa. 



Proteroglypha. Maxilla horizontal, thickened, and not reaching preraaxil- 

 laries anteriorly, in contact with prefrontal, bearing a perforate and usually 

 grooved, immovable tooth. Head generally quadrangular, with flat crown 

 and moderate or short muzzle. Loral plate none. (Cope.) 



Naja. Head high, quadrangular, not very distinct from neck, with rather 

 short, rounded muzzle. Rostral moderate, rounded, sometimes produced 

 backwards and pointed ; anal scutes entire ; subcaudal two-rowed ; one or 

 two fangs behind large anterior teeth, not grooved. 



N. haje (Cleopatra's asp), Seba. Sixth upper labial united with tempo- 

 rals, and forming a very large shield in contact with oculars ; generally with- 

 out marks on neck. 



Habitat. Northwestern Africa- 



JV. tripudians (Cobra di capello), Scheuz. 



Sixth upper labial small, forming a suture with a very large temporal ; 

 generally with a spectacle mark on neck. 



