1894.] OPHLDIA OF TKINIDAD, B. W. I. 503 



in such situations, those thus caught averaging 6 or 7 feet. 

 Individuals vary considerably in the animals they prefer for food. 

 One which we had from the time it was a baby (having the 

 umbilical still attached) was brought up on mice and now eats rats 

 with avidity, but will also eat opossums, snipes, and pigeons. 

 After a meal of the latter he is loath to take rats when feeding- 

 time comes round again. He would not eat a guinea-pig repeatedly 

 offered to him at loug intervals. Another fed readily upon two 

 rats soon after it was caught, and a month later on a guinea-pig. 

 A third, after a fast of 5 months and 20 days, during which he 

 refused rats and guinea-pigs, ate a couple of pigeons. A large 

 Boa fed on fowls and pigeons, and on one occasion ate an old 

 fowl weighing 6 lbs. These snakes are essentially night animals, 

 being very sleepy in the daytime ; but it is questionable whether 

 they are great travellers, one which escaped from an open shed 

 being caught 12 days afterwards disappearing under the floor of 

 the same building only a few yards distant from the box in which 

 it had been confined. Another one after an absence of two months 

 was similarly recovered. If well fed when young, Boas change 

 their skins about every six weeks. A Boa we have watched for 

 some three years changes its skin at intervals varying from five to 

 seven weeks, during which periods it devours six or seven rats. 



In their wild state Boas are found in damp localities, but not in 

 swamps. In the woods at Mayaro hunters frequently have had 

 their dogs caught by them, and Boas have been killed with young 

 deer, Cariacus mmorivagas, and Ocelots in their stomachs. Their 

 droppings contain evidences of the fact that they feed largely on 

 agouti. In captivity they will frequently devour dead rats and 

 other animals, but this is rather the exception than the rule. 

 They all seem to have an aversion to the domestic cat. These 

 snakes differ considerably in their general coloration, but the 

 marking is always very much the same. The ground-colour 

 varies from deep brown to light grey. This difference is probably 

 owing to the various localities from which they come. In Trinidad 

 these snakes couple in February and March — sometimes earlier. 

 Like all the snakes belonging to the Boidae, Boas have anal hooks, 

 which are much more largely developed in some individuals than 

 in others, probably owing to a difference in sex. Boas have been 

 described as using these hooks in climbing trees. Although we 

 have watched them carefully, we have never discovered them 

 making the slightest use of their hooks for the purposes of arboreal 

 locomotion, and their small size would appear to point to the 

 impracticability for such a purpose. These claws, however, ace 

 capable of being slightly protruded and are endowed with 

 considerable mobility. When about to couple, the male extends 

 these hooks at right angles to the body and vibrates them in an 

 extremely rapid manner, scratching, as he does so, the back and 

 sides of his companion. The claws scratching the scales of his 

 mate make a noise which can be distinctly heard two yards off. 

 This habit has also been observed in E/ncrates cenchris. Younsr 



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