236 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



considerable length, requiring several days of persistent ef- 

 fort on the part of the tortoise to cover them. 



"When surprised they draw in their limbs and necks with a 

 deep hiss, and suspend operations until they think the danger 

 past. No amount of noise seems to frighten them and the 

 Ecuadorians assert that they are deaf. A small one, however, 

 taken at Iguana Cove, Albemarle, learned to recognize the 

 voice of its keeper in a few months, and would come to the 

 gate of its pen when called though the keeper was hidden from 

 its sight. 



"The males are sometimes quarrelsome, especially in the 

 breeding season. In fighting the jaws are opened widely, and 

 the animals, raised by outstretched necks and limbs to their 

 greatest height, attack one another. Superior height seems 

 to be quite an advantage in a combat, allowing the taller to 

 bite down upon the head of his adversary. In these fights 

 they seldom succeed in doing much damage. When turned 

 over on their backs they right themselves by swinging their 

 limbs all in the same direction, which causes the animal to 

 rotate and clear the ground, so that by thrusting out their 

 long necks to the ground and pushing with them the body 

 falls over on the plastron. During this operation they usually 

 indulge in much grumbling and groaning as if it were a terri- 

 ble tax on their anatomy. During the breeding season the 

 males are said to 'bellow like bulls.' The 'bellowing' which 

 we heard consisted of a rather low prolonged note which could 

 not have been heard more than a few yards away. 



"The young do not take on their specific characters until 

 nearly adult ; they remain very similar in shape, in all the 

 species for a considerable time. All the young observed pos- 

 sessed striated shells, but adults seem to retain or lose this 

 character indifferently in most of the species. 



"Growth takes place by additions to the outer border of each 

 plate along the soft white seams, and probably continues as 

 long as life exists ; the largest specimens possess the whitish 

 seams which mark the growing edges of the plates. In youth 

 the annual increase is probably much greater than later. A 

 specimen from Iguana Cove, weighing 29 pounds when taken, 

 doubled its original weight in twelve months, accompanied 

 by an increase to the margin of each plate of the carapace of 



