194 



1006. The carapace of the American Box Tortoise (Cistudo clau$a), with some of the 

 marginal scutes removed ; showing the coextension of the marginal plates in 

 this variety, where the degree of eversion is slight. Mm. Leverianum. 



1007. The shell of a young American Box Tortoise the Clouded variety (Cist u Jo 

 clausa; Terrapene nebulosat Bell, Zool. Journ. ii.). Mm. Srit. 



1008. The carapace of a young American Box Tortoise (Cistudo clama). It shows 

 the immature character of the non -eversion of the margin : the keel is well- 

 developed. Mm. Leverianum. 



1009. The shell and skull of a young American Box Tortoise (Cistudo clausa), with 

 the scutes removed. Mm. Srit. 



1010. The shell of the Leverian Box Tortoise (Cistudo Amboinensis, var. Leveriand). 

 The anterior flap of the plastron is articulated to show its mobility on the rest 

 of the plastron. Mus. Leverianum. 



Family Terrestria. 



Genus Testudo (Tortoises proper). 



1011. The skeleton of the great Land Tortoise of the Gallapagos Islands (Testudo 

 elephantopus}. 



A section of the carapace and plastron has been removed from the right side to expose the 

 dorsal and sacral vertebrae and the disposition of the scapular and pelvic arches. The first 

 eight vertebrae are free, moveable, and ribless ; the fourth of these ' cervical ' vertebrse has a 

 much-elongated centrum, which is convex at both ends ; the eighth is short and broad, with 

 the anterior surface of the body divided into two transversely elongated convexities, and the 

 posterior part of the body forming a single convex surface divided into two lateral facets ; 

 the under part of the centrum is carinate. The neural arch, which is anchylosed to this 

 centrum, has two anterior zygapophyses looking upwards and two posterior ones looking 

 downwards : the spine is short, broad, obtuse, and overarched by the broad expanded nuchal 

 plate. The first dorsal vertebra is, also, short and broad, with two short and thick pleur- 

 apophyses, articulated by one end to the expanded anterior part of the centrum, and united 

 by suture at the other end to the succeeding pair of ribs. The head of each rib of the 



