106 Zoological Society : — 



Having lately received more perfect specimens of some of the 

 Indian Box Tortoises, I am induced to suggest their arrangement as 

 follows : — 



The Tortoises belonging to the tribe Cistudina are characterized 

 by having the sternum attached to the back by a ligamentous suture 

 on each side, and divided across the centre by a similar cross suture, 

 leaving the front and hind lobe more or less moveable. 



In the normal Cistudina, which have the lobes of the sternum 

 moveable at all ages, the cartilaginous sutures and the suture between 

 the pectoral and ventral shields of the sternum are at the same situ- 

 ation ; and the lobes of the sternum are broad, as broad as the open- 

 ing of the thorax, and cover the legs when they are contracted. 



The normal Cistudince may be divided into genera, according to 

 the more or less aquatic habits of the animal, as indicated by the 

 structure of the feet. 



I. Sternum-lobes unequal ; front shorter, almost free from the sym- 

 physis. The hind foot slender, elongate ; toes very unequal, 

 second longest. N. America, 



1. CiSTUDO. 



Thorax convex, solid ; sternum rounded or truncated before and 

 behind ; the front lobe smaller, almost free from the symphysis. 

 The fore legs with large shields in front ; the toes short, enclosed, 

 not webbed, with short conical claws. The hind feet elongate, nar- 

 row, with the second toes produced ; the rest short, nearly enclosed, 

 not webbed; the soles of the feet with subequal moderate-sized 

 scales, the hinder edge rounded. 



N. America. 



* The hind feet with small hinder or outer fourth toes. Cistudo. 

 CisTUDO CAROLINA, Gray, Cat. Shield Rept. B.M. p. 39. 

 Of which C. ornata and C. major, Agassiz, seem to be varieties. 



** The hind feet loithout any small fourth toes. Onychotria. 

 Cistudo mexicana. Gray, Cat. I. c. p. 40. 



See also C. triunguis, Agassiz, which is. said to be smaller than 

 C Carolina and C. mexicana. 



Dr. Holbrook describes and figures Cistudo Blandingii (t. 3) as a 

 separate species, because it has a head like Emys, the upper jaw 

 deeply emarginate in front, the front lobe of the sternum less ele- 

 vated. On these characters Leconte refers it to Lutremys, and 

 Agassiz to Emys, as restricted by Bonaparte, who regards E. europcea 

 as the type. The figures of Holbrook look very like Cistudo Caro- 

 lina ; but Agassiz, who forms for it a subfamily, describes it as much 

 more depressed. It is probably distinct ; but I have never seen an 

 American Box Tortoise that could be arranged or confounded, as 

 Leconte has done this, with our European Lutremys. It certainly 

 is not E. Meleagris of Shaw, as Agassiz believes. 



