THE GALAPAGOS TORTOISES. 289 



and more rounded. Between the anal plates the notch is more shallow; gulars 

 and anals are widened, the former have thickened upward, the latter are swollen 

 downwards. Along each side of the medial concavity there is a great rounded 

 prominence. An extreme form of the female in medium size is that shown on 

 Plate 33, a more common form on Plate 32. 



Specimens of about three times the length of the types are figured in Plates 

 29, 30, 31, 36. They emphasize the tendencies prominent on those of the 

 medium sizes besides indicating others acquired on approach of maturity or 

 depending on age, together with those dependent wholly or partly on sex. In 

 the majority these features will be sufficiently evident from the illustrations. 

 The large females on Plates 31, 35 as compared with those of the smaller group, 

 Plate 32, have more fullness or roundness in the vertebral and in the costal 

 plates and have much greater concavity in the sternum. They are even more 

 concave than in the male, Plates 29, 30, fig. 3; the latter is more elongate and 

 more depressed on the back and a trifle narrower across the humeral region. 

 Being less deep in the sternal concavity may be a peculiarity of this specimen 

 as the difference is not great. Plate 28, fig. 1 and Plate 31 pertain to the 

 female described in Dr. Jackson's article, The anatomical description of the 

 Galapagos tortoise, Boston Journal of Natural History, 1837, 1, p. 443. Plate 

 29 is the male discussed in the same article; it is outlined on Plate 30, from 

 Giinther's figures in the Nov. Zool., 1902, 9, PI. 16 and 17. '^r- 



These specimens were secured by the U. S. S. Potomac. Santa Maria 

 (Charles) was the only island of the group visited. In the latter part of May, 

 1834, the vessel was at Boston, and in June the donation of "two gigantic 

 Galapagos tortoises (living) weighing near three hundred and twenty pounds 

 each, by Capt. John Downes (U. S. Navy) is recorded by the Boston Society of 

 Natural History. The Potomac was at Santa Maria from August 31 to Sep- 

 tember 10, according to Reynolds's account, p. 547, "a large number of the crew 

 were daily on shore after terrapin, and frequently exposed throughout the day 

 to a hot sun, with these immense animals on their backs, travelling over the 

 broken lava." The male of the Downes and Jackson specimens was examined 

 by Bam* and became the type of his T. galapagoensis. Afterward it crossed the 

 Atlantic and was described and figured by Giinther, 1902. The photograph, 

 Plate 35, a fine specimen inscribed with the legend "Ship Abigail 1835 Bj. 

 Clark Master," is probably from a native of the same island, Santa Maria. 

 The Abigail was a whaling vessel from New Bedford, Mass. The specimen is 

 No. 11064 M. C. Z., received from the Boston Society of Natural History in 

 exchange. 



