228 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Sek. 



can exist. without food; for I have been well assured that they 

 have been piled away among the casks in the hold of a ship, 

 where they have been kept eighteen months, and when killed 

 at the expiration of that time, were found to have suffered no 

 diminution in fatness or excellence. They carry with them a 

 constant supply of water, in a bag at the root of the neck, 

 which contains about two gallons, and on testing that found in 

 those we killed on board, it proved perfectly fresh and sweet. 

 They are very restless when exposed to the light and heat of 

 the sun, but will lie in the dark from one year's end to the 

 other without moving. In the daytime, they appear remark- 

 ably quick-sighted and timid, drawing their head into their 

 shell on the slightest motion of any object; but they are 

 entirely destitute of hearing, as the loudest noise, even the 

 firing of a gun, does not seem to alarm them in the slightest 

 degree, and at night or in the dark they appear perfectly 

 blind. * * * 'pj^e shells of those of James Island are 

 sometimes remarkably thin and easily broken, but more par- 

 ticularly so as they become advanced in age; when, whether 

 owing to the injuries they receive from their repeated falls in 

 ascending and descending the mountain, or from injuries 

 received otherwise, or from the course of nature, their shells 

 become very rough, and peel off in large scales, which renders 

 them very thin and easily broken. Those of James Island 

 appear to be a species entirely distinct from those of Hood 

 and Charles islands. The form of the shell of the latter is 

 elongated, turning up forward in the manner of a Spanish 

 saddle, of a brown color and of considerable thickness. They 

 are very disagreeable to the sight, but far superior to those of 

 James Island in point of fatness, and their livers are consid- 

 ered the greatest delicacy. Those of James Island are round, 

 plump, and black as ebony, some of them handsome to the eye, 

 but their liver is black, hard when cooked, and the flesh alto- 

 gether not so highly esteemed as the others. * * * [The 

 tortoises of Hood's Island] were of a quality far superior to 

 those found on James Island. They were similar in appearance 

 to those of Charles Island, very fat and delicious." 



Porter proceeded, after his cruise round the Galapagos, to 

 the Marquesas Islands, making a prolonged stay at Madison 

 [Rotumah] Island, where he "distributed from his stock sev- 



