592 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



in the center of each scale. It is one of the most attractive of the py- 

 thons in captivity and the specimens in the collection are much more 

 active than is usual with large snakes. A closely related form known 

 as the carpet snake has a much wider distribution in Australia. 



The common boa, or boa constrictor {Constrictor constrictor) is a 

 tropical American species of large size, but considerably smaller than 

 the Anaconda and the larger pythons. It is said rarely to reach a 

 length of 12 feet. Several examples are shown, the largest of which 

 came from Trinidad and is about 10 feet in length. A small speci- 

 men of the boa was found in the Washington Market packed with a 

 bunch of bananas, and was sent to the park. This involuntary stow- 

 away is doing nicely in his new home. Other species of boas are 

 found in South America, the West Indies, and, strangely enough, in 

 Madagascar. The tree boa from Trinidad {Boa enydris), in a near- 

 by case, is of a smaller species, yellow in color, and with a head much 

 larger in proportion to the size of the serpent. Although an ill- 

 tempered snake, it is, like the boa constrictor, a nonpoisonous species. 

 It sometimes grows to a length of 6 or 7 feet. 



Many species of North American snakes are usually on exhibition. 

 Most of these are of comparatively small size but some of them are 

 of great beauty and others are interesting because of their terrible 

 appearance and deadly poison. In the latter class may be men- 

 tioned the rattlesnakes and copperheads 



The rattlesnakes are confined to America where many species are 

 known, the majority of which are found in the western United States. 

 The common or banded rattler {Crotalus horrklu.s) was formerly 

 found in many parts of the Eastern States, north into Maine, but has 

 now disappeared from much of its former range. It sometimes 

 grows to 5 feet or more in length. The largest rattler is the dia- 

 mond-back (C. adamanteus) which in its typical form in the 

 Southern States reaches an immense size. Many specimens are on 

 record from Florida which measured over C feet in length and there 

 are apparently authentic accounts of diamond-backs of between 8 and 

 9 feet. The bite of one of these large rattlers is very likely to prove 

 fatal. 



Closely related to the rattlesnakes are the moccasin {Agkistrodon 

 piscivorus) and the copperhead {A. mokasen). Both are poisonous 

 species. The copperhead is one of the most dangerous snakes 

 in the Eastern and Southern States because he holds his own in 

 thickly settled communities; they are not uncommon about Washing- 

 ton, especially along the upper Potomac above the city. Adult 

 specimens are commonly from 24 to 30 inches long. In color, the 

 copperhead is hazel brown, with a series of hourglass-shaped darker 

 blotches along the back. Equally venomous is the moccasin, or 



