128 



the observations made on two females of this snake by a man of credi- 

 bility who had captured them a"nd kept them until they had produced 

 young (22, xxi, 216). According to these observations, the young passed 

 freely into and out of the mother's mouth until they were a month old. 

 After this time the mother was very attentive to the young, as I saw 

 myself 



Genus CROTALUS, Linn. 



Crotalus, Linnteus, 1758, 64, ed. x, i, 214; Baird and Girard, 1853, 

 6, 1 ; Garman, 1883, 13, 110. 



Form stout. Head triangular. Crown-shields fewer than nine, the 

 vertical and occipitals replaced by numerous small scales. A pit in front 

 of nostril. Anal and most of the subcaudals entire. Tail with a rattle. 



Crotalus horridus, Linn. 

 Banded Rattlesnake. 



Orotalus horridus, Linnseus, 1758, 64, ed. x, i, 214; Garman, 1883, 13,. 

 115, pi. 9, fig. 1; Crotalus durissus, Holbrook, 1842, 54, iii, 9, pi. 1; 

 Baird and Girard, 1853, 6,1. 



Body elongated, tapering toward head and tail. The neck slender. 

 Tail short, from one-eighteenth to one-eighth the total. Head broad, 

 triangular, flattened above, concave in the interorbital region. Snout 

 blunt. Back portion of head forward to the interorbital region covered 

 with small keeled or tuberculated scales. Scales of the cheeks larger 

 and smooth. Superciliaries large and overhanging the eyes. Anteor- 

 bitals 2, the lower slender and overarching the pit. Lorals 2. Nasals 

 2, the anterior largest. Rostral higher than broad. Prefrontals 2, post- 

 froutals 4, in a transverse row, the inner pair sometimes replaced by 

 small scales. Upper labials 12 to 16, separated from the orbit by three 

 or four rows of scales. Lower labials 13 to 18. Eye small. Scales 

 keeled, except those of the outer row ; number of rows 23 or 25. Ven- 

 tral plates 165 to 175. Subcaudals 19 to 25. Rattle of the adult par- 

 allelogrammic, with a median groove. 



Ground color above cream yellow to yellowish brown, and even black. 

 There are three series of dark spots, a dorsal and a lateral on each side. 

 The dorsal blotches are large, occupying in breadth about twelve rows of 

 scales and about four in length. These are nearly black around the bor- 

 ders and paler in the centers. The lateral series has the spots smaller. 

 Posteriorlj'^ the three series coalesce, so as to form zig-zag, dark-edged, 

 transverse bands. All the spots and bands are bordered with sulphur 

 yellow. Tail of the adults usually black. The color below is yellow, 

 with some mottlings and sprinklings of black. Upper lip sulphur yel- 

 low ; lower lip paler. 



