15. BOA. 117 



1. Boa constrictor. 



Mnn. Amoen. Acad. i. p. 497, pi. xvii. fig. 3 (1749). 



Boa constrictor, Linn. 8. N. i. p. 373 (1766) ; Schneid. Dmkschr. Ak. 



Munch, vii. 1821, p. 114, pi. vi. fig. 1 ; Wied, Beitr. Nat. Bras. i. 



p. 211 (1825) ; Bum. ^Bibr. vi. p. 607 (1844) ; Gray, Cat. p. 100 



(1849) ; Jan, Icon. OSn. p. 81, 1. 6, pi. i. (1864). 

 Constrictor formosissimus, Laur. Syn. JRept. p. 107 (1768). 



rex-serpentum, Laur. I.e. ■ 



auapex, Laur. I. c. p. 108. 



Boa constrictiix, Schneid. Hist. Amph. ii. p. 247 (1801). 



constrictor, part.. Baud. Bept. v. p. 174 (1803) ; Schleg. Phys. 



Serp. ii. p. 373, pi. xiv. figs. 6 & 7 (1837). 



Snout slightly prominent in the adult, obliquely truncate in the 

 young. Eostral a little broader than deep ; symphysial at least 

 as long as broad ; head-scales small, slightly larger on the snout ; no 

 shields ; one of the preeoculars slightly enlarged ; 18 to 24 scales 

 across the forehead, from eye to eye ; 16 to 20 scales round the eye, 

 ■which is separated from the labials by two or three series of scales ; 

 21 to 25 upper labials. Scales in 81 to 95 rows. Ventrals 234- 

 243 ; anal entire ; suboaudaJs 49-60. Pale brown above, with 15 

 to 20 dark brown cross bars widening on each side and, if connected 

 by a dark dorso-lateral streak, enclosing large elongate oval or 

 elliptical spots of the pale ground-colour; a light longitudinal line 

 in the outer widened portion of the dark cross bars ; on each side a 

 series of large dark brown spots with light centres, most of which 

 alternate with the dorsal bars ; on . the tail the markings become 

 much larger, brick-red, edged with black, and separated by narrow 

 yellowish interspaces ; head with a dark brown median line extend- 

 ing from between the nostrils to the nape, widening behind, some- 

 times loop-shaped j a crescentic blackish marking on the rostral ; a 

 dark brown streak on each side of the head, passing through the 

 eye, and sending down a process between the end of the snout- and 

 the eye ; a dark brown bar below the eye and two on each side of 

 the lower lip ; beUy yellowish, dotted, or dotted and spotted with 

 black. 



Total length 3355 millim. ; tail 330. Beaches to 12 feet 

 {Wied). ^ ^ 



South America, from Venezuelalto Buenos Ayres. j - 



a, b. Yg. (Sc. 89, 87 ; V. 238, ' Tobago. W. A. Ludlam, Esq. 



237; 0.49,55). [P.]. 



c. Yg. (Sc. 95 ; V. 240 ; 0. 50). Trinidad. 



d. Yff. (Sc. 93 ; V. 239 ; 0. 54). Cayenne. 



e. c? (Sc. 89 ; V. 238 ; 0. 56). Para. J. P. Smith, Esq. [P.]. 

 /. Yff. (Sc.87; V. 243;C. 51). Pernambuco. W. A. Forbes, Esq. 



[P.], 



g-h. Yg. (Sc. 85, 85 ; V. 241, Moyobamba, Mr. A. H. Eoff [CI. 



238 ; 0. 56, 50). N.E. Peru. 



i, h,l. 2 & hgr., stffd. S. America. 



m. Ad., skeL Trinidad. Lord Harris [P.]. 



, n. Hgr., skel. ? 



0. Hgr., skull. Cayenne. 



